Are you still creating invoices manually using Word, Excel or paper?
As your business grows, invoicing can become much more than simply generating a document.
You may need to manage:
Customer information
Products and services
Prices
Discounts
Taxes
Invoices
Quotations
Receipts
Payments
Outstanding balances
Recurring invoices
Credit notes
Reports
Payment confirmations
Customer statements
When these activities are handled manually, mistakes become easier to make and tracking outstanding payments becomes difficult.
At WATT-IF LTD, we develop custom invoicing software designed around your business processes, whether you are a small business, professional services company, retailer, distributor or growing organization.
🧾 Need a Custom Invoicing System?
WATT-IF can develop an invoicing solution for creating invoices, tracking payments, managing customers, generating receipts, producing reports and integrating with other business systems.
[Request an Invoicing System Consultation]
Invoicing software is a digital system that helps businesses create, manage and track invoices and related payment information.
Instead of creating an invoice manually:
Customer details
↓
Products/services
↓
Prices
↓
Invoice
↓
Send to customer
↓
Record payment
↓
Generate receipt
an invoicing system can bring these processes together.
Consider a business issuing 20, 50 or 100 invoices every month.
The company needs to know:
Which invoices have been paid?
Which are overdue?
How much is outstanding?
Which customers owe money?
How much was collected this month?
Which invoices were cancelled?
Which payments belong to which invoices?
With spreadsheets, this can become difficult to manage.
A properly designed invoicing system can provide a centralized record.
Depending on your requirements, WATT-IF can develop an invoicing platform with features such as:
Customer management
Product management
Service management
Invoice creation
Invoice numbering
Quotations
Proforma invoices
Receipts
Payment tracking
Outstanding balances
Customer statements
Discounts
Taxes
Credit notes
Recurring invoices
Invoice reminders
Reports
User permissions
Payment integration
Accounting integration
An invoicing system starts with customer information.
A customer profile can contain:
Customer name
Business name
Phone
Address
Tax information where applicable
Customer number
Invoice history
Payment history
Outstanding balance
Instead of entering customer information repeatedly, the system can retrieve it when creating an invoice.
If you repeatedly sell the same products or services, the system can store them.
For example:
Item | Price |
|---|---|
Website Development | KSh 80,000 |
Website Maintenance | KSh 10,000 |
Hosting | KSh 8,000 |
SEO Services | KSh 20,000 |
When preparing an invoice, the user can select the appropriate service instead of typing it every time.
Prices can be configured according to your business requirements.
A typical invoice may include:
Company information
Customer information
Invoice number
Invoice date
Due date
Items/services
Quantity
Unit price
Discount
Tax
Total
Payment instructions
The system generates the invoice based on the configured format.
Instead of manually deciding invoice numbers, the system can generate them.
For example:
INV-0001
INV-0002
INV-0003
This reduces the possibility of accidentally using duplicate invoice numbers.
The numbering structure can be customized.
Your invoice is also part of your brand.
A custom invoicing system can use your:
Logo
Brand colours
Company information
Contact details
Payment instructions
This gives invoices a consistent professional appearance.
🎨 Want Branded Business Invoices?
WATT-IF can design your invoicing interface and invoice templates around your company's branding.
[Request a Custom Invoice Design]
Many businesses issue quotations before creating invoices.
The workflow can be:
Customer enquiry
↓
Quotation
↓
Customer accepts
↓
Invoice
Instead of creating the invoice from scratch, the system can potentially convert an approved quotation into an invoice.
Some businesses require proforma invoices before a final invoice.
The system can support different document types according to the company's workflow.
After receiving payment, the system can generate a receipt.
For example:
Invoice
KSh 50,000
↓
Payment received
KSh 50,000
↓
Receipt generated
This creates a clear payment record.
An invoicing system should answer one important question:
Has this invoice been paid?
Invoices can have statuses such as:
Draft
Sent
Partially Paid
Paid
Overdue
Cancelled
The exact statuses depend on the system design.
Customers don't always pay the entire invoice at once.
For example:
Invoice: KSh 100,000
Payment 1: KSh 40,000
Payment 2: KSh 30,000
Balance: KSh 30,000
The system can track these transactions and calculate the remaining balance.
Management can see how much customers owe.
For example:
Customer | Invoice | Amount | Balance |
|---|---|---|---|
Customer A | INV-101 | 100,000 | 40,000 |
Customer B | INV-102 | 50,000 | 0 |
Customer C | INV-103 | 75,000 | 75,000 |
This can help the business prioritize collections.
A customer statement can show:
Previous invoices
Payments
Credit notes
Outstanding balances
This is useful for businesses that provide services or products on credit.
Invoices can have payment terms.
For example:
Invoice Date: 1 August
Due Date: 15 August
The system can identify invoices that have passed their due date.
Depending on the system configuration, automated reminders can be sent before or after the due date.
For example:
Your invoice INV-102 is due on 15 August.
Another reminder could be sent after the due date.
Notifications can potentially use:
SMS
WhatsApp through an appropriate integration
In-app notifications
For Kenyan businesses, M-Pesa can be an important part of the invoicing workflow.
A possible process is:
Invoice
↓
Customer receives payment instructions
↓
Customer pays
↓
Payment service
↓
System receives confirmation
↓
Invoice status updated
↓
Receipt generated
The exact implementation depends on the payment service and applicable API capabilities.
💳 Want Customers to Pay Directly From Your Invoice?
WATT-IF can assess your invoicing and payment workflow and develop appropriate payment integrations, including applicable M-Pesa and card-payment options.
[Discuss Payment Integration]
Businesses that accept cards can potentially connect their invoicing system to a supported payment provider.
The workflow may look like:
Invoice
↓
Pay Now
↓
Payment Provider
↓
Customer pays
↓
Payment confirmation
↓
Invoice marked paid
This can make payment collection easier for customers.
Instead of simply sending a PDF invoice, you can potentially send customers a link to view and pay an invoice online.
For example:
Invoice INV-1001
Amount: KSh 25,000
[Pay Invoice]
This can connect the invoice to an online payment workflow.
Some businesses have customers who pay regularly.
Examples include:
Hosting
Software subscriptions
Maintenance
Consulting
Cleaning services
Security services
Memberships
Instead of manually creating an invoice every month, recurring billing functionality can be developed.
For example:
Customer
↓
Monthly subscription
↓
Automatic invoice
↓
Payment reminder
↓
Payment
Sometimes an invoice needs to be adjusted.
For example:
Customer returns goods
Service is cancelled
Invoice was overcharged
Discount needs to be applied
A credit note workflow can be developed to record the adjustment appropriately.
The system can support different discount structures.
For example:
Product price: KSh 10,000
Discount: 10%
Net amount: KSh 9,000
Discount rules can be configured according to your business requirements.
Businesses may need tax information displayed on invoices.
The system can be configured according to applicable tax requirements and the company's accounting workflow.
For businesses operating in Kenya, tax configuration should be reviewed against current requirements.
Businesses operating in Kenya should consider applicable electronic invoicing and tax requirements when designing invoicing software.
A custom invoicing system should therefore be designed with compliance requirements in mind rather than simply generating attractive PDF documents.
Where integration with relevant tax or electronic invoicing systems is required, WATT-IF can assess the available technical integration requirements and incorporate them into the project scope.
Customers often expect invoices in PDF format.
The system can generate downloadable documents containing:
Company branding
Customer details
Invoice number
Items
Taxes
Total
Payment information
The PDF can then be sent to the customer.
Instead of downloading the invoice and attaching it manually to an email, the system can potentially send it directly.
For example:
Create invoice
↓
Generate PDF
↓
Send email
↓
Customer receives invoice
This saves time.
For businesses that need fast communication, SMS integration can be useful.
For example:
Invoice INV-001 of KSh 25,000 has been issued. Please check your email for details.
SMS functionality requires integration with an appropriate SMS provider.
Management can have an overview of invoicing activity.
For example:
KSh 150,000
KSh 720,000
KSh 1,450,000
KSh 230,000
18
A dashboard can make financial information easier to understand.
The system can generate reports such as:
Sales by period
Invoices issued
Paid invoices
Unpaid invoices
Overdue invoices
Customer balances
Revenue by product
Revenue by service
Payments received
Tax-related summaries
Reports can be customized according to management needs.
Not everyone in the company needs access to everything.
For example:
Can:
Create quotations
Create invoices
View customers
Can:
Record payments
Generate receipts
View financial reports
Can:
View dashboards
View reports
Can:
Manage users
Configure the system
This helps control access.
For important business records, it can be useful to know who performed an action.
For example:
Invoice INV-001
Created by:
Sales User
Date:
5 August 2026
Payment recorded by:
Finance User
This creates accountability within the system.
If your business has several branches, the system can support branch-specific operations.
For example:
WATT-IF Head Office
Nairobi Branch
Mombasa Branch
Kisumu Branch
Management can potentially view consolidated or branch-specific reports.
Multiple employees can use the same system while having different permissions.
For example:
Sales Team
Creates invoices.
Finance
Records payments.
Management
Views reports.
This is more organized than sharing a single Excel file.
If your business sells physical products, invoicing can be connected to inventory.
A possible workflow:
Sale
↓
Invoice
↓
Inventory
↓
Stock reduced
This avoids entering the same sale twice.
Businesses with physical shops can connect their POS and invoicing systems.
For example:
POS transaction
↓
Invoice
↓
Payment
↓
Receipt
↓
Inventory update
The exact architecture depends on the existing POS.
If your sales team uses a CRM:
Lead
↓
Customer
↓
Quotation
↓
Invoice
↓
Payment
API integration can connect these stages.
This can create a more complete sales-to-payment workflow.
An invoicing system can potentially integrate with accounting software.
For example:
Invoice created
↓
API
↓
Accounting system
This can reduce manual transfer of invoice information.
A custom invoicing system needs a structured database.
The database can contain:
Customers
Products
Invoices
Invoice items
Payments
Receipts
Users
Taxes
Discounts
A properly designed database helps keep records organized.
At WATT-IF, we don't start by simply designing an invoice screen.
We first understand your business.
We ask questions such as:
What do you sell?
How many invoices do you issue?
Do you sell products or services?
Do customers pay immediately?
Do you offer credit?
Do you accept M-Pesa?
Do you accept cards?
Do you have branches?
Do you already use accounting software?
Do you have a POS?
Do you need recurring billing?
This determines the scope.
For example:
Customer enquiry
↓
Quotation
↓
Approval
↓
Invoice
↓
Payment
↓
Receipt
↓
Accounting
This workflow becomes the foundation of the system.
We structure the information required by the business.
For example:
Customers
connect to
Invoices
which connect to
Payments
which connect to
Receipts
This makes the system easier to manage.
We design interfaces for:
Dashboard
Customers
Products
Quotations
Invoices
Payments
Receipts
Reports
Users
The interface can be branded to your business.
We build the required functionality based on the approved scope.
Where required, integrations can include:
M-Pesa
Card payments
Accounting
POS
CRM
Inventory
SMS
Website
Mobile application
We test scenarios such as:
Create invoice
Edit invoice
Cancel invoice
Record payment
Generate receipt
Partial payment
Overpayment
Outstanding balance
Payment failure
Duplicate transaction
We can train relevant staff on:
How to create quotations and invoices.
How to record payments and generate reports.
How to use dashboards and reports.
How to manage users and system settings.
The system can be deployed according to the agreed infrastructure.
This may include:
Hosting
Database
Domain
SSL
Backups
User accounts
Your invoicing requirements may change as your business grows.
You may later need:
New reports
New payment methods
Mobile application
Customer portal
Additional integrations
Multi-branch functionality
The system can be extended based on the agreed development scope.
There is no universal price.
A basic invoicing system could contain:
Customers
Products/services
Invoices
Receipts
Payments
Basic reports
A more advanced system could include:
M-Pesa
Card payments
Recurring billing
Customer portal
Accounting integration
Inventory
POS
CRM
Mobile application
Multi-branch
Advanced reporting
Naturally, these projects have different development requirements.
How many employees will use the system?
Do you need only invoicing or a complete sales platform?
Do you need M-Pesa, cards or other payment options?
Do invoices need to synchronize with accounting software?
Does invoicing need to reduce stock?
Do physical sales need to connect?
Do customers need to log in and view invoices?
Do you need Android/iOS access?
How advanced should the reporting be?
Are there specific electronic invoicing or tax-related requirements?
The timeline depends on the scope.
A basic system is much faster to develop than an enterprise invoicing platform integrated with:
POS
Inventory
Accounting
M-Pesa
Card payments
CRM
Mobile application
After understanding your requirements, WATT-IF can provide a more accurate project timeline.
Both options can make sense.
May be appropriate if:
Your requirements are standard.
You want to deploy quickly.
You don't need extensive customization.
May be appropriate if:
Your workflow is unique.
You need integrations.
You require custom reports.
You want your own system.
You need specific approval processes.
You want the software to grow with your business.
The right choice depends on your requirements and budget.
You may need a better invoicing system if:
You create invoices using Word.
You create invoices using Excel.
You use paper invoices.
You manually calculate outstanding balances.
Customers frequently ask for invoice copies.
You don't know which invoices are overdue.
You manually reconcile payments.
You manually prepare receipts.
Your sales team and finance team use separate records.
You have multiple invoice templates.
You struggle to find old invoices.
You manually send every invoice by email.
Customers have difficulty paying invoices.
You don't have a customer statement system.
You use a separate spreadsheet for payment tracking.
Your website doesn't connect to your invoicing system.
Your POS doesn't connect to inventory.
Your accounting software doesn't receive invoice information automatically.
Your business has multiple branches.
You are growing and your current invoicing process cannot keep up.
It depends on the required features, integrations, users and customization.
Yes.
Yes, depending on the workflow.
Yes.
Yes.
Yes.
Yes, where suitable payment integrations are implemented.
WATT-IF can assess and implement applicable M-Pesa integration requirements.
Yes, through supported payment providers.
Yes.
Yes, through an appropriate SMS integration.
Yes.
Yes.
The numbering structure can be configured according to the agreed requirements.
Yes.
This functionality can be developed.
Yes.
Yes.
Yes.
Yes, where the accounting platform provides suitable integration capabilities.
Yes, subject to the POS's technical integration capabilities.
Yes.
Yes.
Yes.
Yes.
Yes.
A web-based system can be deployed for remote access, subject to the chosen infrastructure and security configuration.
Yes.
Yes, support and maintenance can be arranged.
The biggest advantage of custom development is that the software is designed around your business rather than forcing your business to work around the software.
At WATT-IF, we can combine:
Software Development
Database Development
API Integration
Payment Integration
Web Development
Mobile Application Development
to create a connected business solution.
For example:
Customer
↓
Website
↓
Order
↓
Invoice
↓
M-Pesa/Card Payment
↓
Payment Confirmation
↓
Receipt
↓
Inventory
↓
Accounting
That's much more powerful than simply generating a PDF invoice.
Your invoice should not be an isolated document.
It can be part of a larger business workflow.
Imagine:
Lead
↓
Customer
↓
Quotation
↓
Order
↓
Invoice
↓
Payment
↓
Receipt
↓
Inventory
↓
Accounting
↓
Reports
WATT-IF can help you design and develop the technology required to connect these processes.
🚀 Let's Build Your Invoicing System
Whether you're currently using Excel, Word, paper invoices, an existing invoicing application or a complete accounting system, WATT-IF can assess your current process and help you determine what should be automated.
[Request a Custom Invoicing System Quote]
[Discuss M-Pesa & Card Payment Integration]
[Talk to WATT-IF About Your Business]