Invoice Generation System - Complete Guide
Last Updated: 2026-05-27 | Applies to: IK v1.2+ | Role: Administrator, Accountant
Understanding Invoice Generation
InstitutionKit's invoice system automatically:
Pulls assigned fees for each student
Calculates previous unpaid balances
Creates monthly invoices with detailed breakdowns
Marks old unpaid invoices as "transferred" to new ones
The Invoice Page Layout
Navigate to: 💰 Fee Management → 🧾 Invoices
Page Sections:
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┌─────────────────────────────────────────────────────┐│ 📋 GENERATE / UPDATE INVOICES ││ [Select Class ▾] [Generate] [📧 Send Emails] [📊 Status]│├─────────────────────────────────────────────────────┤│ 🔍 FILTERS ││ Class: [All ▾] Search: [_______] [Filter] [Reset]│├─────────────────────────────────────────────────────┤│ 📊 STATUS QUICK FILTERS ││ [All] [Unpaid] [Partial] │├─────────────────────────────────────────────────────┤│ 📄 ALL INVOICES (Table) ││ Roll# | Title | Student | Total | Paid | Status... │└─────────────────────────────────────────────────────┘
Step 1: Generating Invoices for a Class
Select a class from dropdown
Click "Generate / Update Invoices"
System processes all students in that class
Success message shows count
What happens behind the scenes:
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For EACH student in selected class:├── Get all assigned monthly fees (from student_fees table)├── Calculate previous unpaid balances from OLD invoices├── Check if THIS month's invoice already exists│ ├── EXISTS → Update total, recreate items│ └── NEW → Create invoice with due date (+10 days)├── Add current month fee items (with month prefix)├── Add previous balance as detailed line items└── Mark old unpaid invoices as "transferred"
The Invoice Creation Logic
Monthly Fee Detection:The system looks for fees with "Monthly" in their name:
"Monthly Tuition Fee" → Included
"Monthly Transport Fee" → Included
"Annual Registration Fee" → Skipped (not monthly)
Previous Balance Calculation:
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Student: John Doe├── April Invoice: $500 (unpaid) → Balance: $500├── March Invoice: $200 (partial, paid $100) → Balance: $100└── Total Previous Balance: $600New May Invoice:├── May Monthly Tuition: $500├── Outstanding April: $500├── Outstanding March: $100└── Total: $1,100
Invoice Items Example:
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May 2026 Fee Invoice #1045├── May Tuition Fee: $500.00├── May Transport Fee: $100.00├── Outstanding April Fee: $500.00├── Outstanding March Fee: $100.00└── Total: $1,200.00
Understanding Invoice Statuses
| Status | Meaning | How It Happens |
|---|---|---|
| unpaid | No payment received | Default for new invoices |
| partial | Some payment made | When 0 < paid < total |
| paid | Fully settled | When paid ≥ total |
| transferred | Balance moved to newer invoice | Old unpaid invoices auto-marked |
Transferred Status:When a new monthly invoice is generated, all previous "unpaid" invoices for that student are marked as "transferred". Their balances are added as line items in the new invoice. This prevents duplicate payment tracking.
Step 2: Filtering Invoices
Filter by Class:
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[All Classes ▾]├── Grade 1├── Grade 2├── Grade 3└── ...
Search:Type student name or roll number to find specific invoices.
Status Quick Filters:
All - Every invoice
Unpaid - Only unpaid (red status)
Partial - Partially paid (orange status)
Invoice Table Columns
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┌──────┬─────────────────┬────────────┬───────┬───────┬────────┬────────────┬──────────┐│Roll #│ Title │ Student │ Total │ Paid │ Status │ Date │ Actions │├──────┼─────────────────┼────────────┼───────┼───────┼────────┼────────────┼──────────┤│ 1042 │ May 2026 Fee │ John Doe │ $1,200│ $600 │ PARTIAL│ 01-05-2026 │[View][Edit]││ 1041 │ May 2026 Fee │ Jane Smith │ $800 │ $800 │ PAID │ 01-05-2026 │[View][Edit]││ 1040 │ April 2026 Fee │ Bob Wilson │ $500 │ $0 │ TRANSF.│ 01-04-2026 │[View][Edit]│└──────┴─────────────────┴────────────┴───────┴───────┴────────┴────────────┴──────────┘
Status Colors:
🟢 Green = Paid
🟠 Orange = Partial
🔴 Red = Unpaid
⚫ Gray = Transferred
Step 3: Viewing a Single Invoice
Click "View" on any invoice to see:
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┌─────────────────────────────────────────┐│ Invoice #1045 [← Back] │├─────────────────────────────────────────┤│ Student: John Doe ││ Class: Grade 5 ││ Status: Partial │├─────────────────────────────────────────┤│ ITEM AMOUNT ││ May Tuition Fee $500.00 ││ May Transport Fee $100.00 ││ Outstanding April Fee $500.00 ││ Outstanding March Fee $100.00 ││ ───────────────────────────────────── ││ TOTAL: $1,200.00 ││ PAID: $600.00 ││ BALANCE: $600.00 │├─────────────────────────────────────────┤│ [📄 Download PDF] │└─────────────────────────────────────────┘
Article 20: Invoice Payment Recording
Apprentice Lesson Setup
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Chapter: Fee & Invoice SystemLesson Title: "Recording Payments and Managing Transactions"Lesson Type: Step-by-Step GuideLabels: [Admin] [Accountant] [Guide]
Article Content
Last Updated: 2026-05-27 | Applies to: IK v1.2+
Recording a Payment (AJAX System)
From the single invoice view, use the payment form:
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┌─────────────────────────────────────────┐│ Record Payment │├─────────────────────────────────────────┤│ Payment Amount: [$_______] ││ Payment Date: [2026-05-27] ││ Payment Method: [Cash ▾] ││ Options: Cash / Bank Transfer / ││ Credit Card / Check ││ Notes: [_______________] ││ ││ [Record Payment] │└─────────────────────────────────────────┘
Validation Rules:
Payment amount must be > 0
Payment cannot exceed balance due
All fields required except notes
What happens on submit:
AJAX call validates amount
Updates
invoice.amount_paidAuto-calculates new status (partial/paid)
Creates transaction record
Returns updated UI without page refresh
Response Updates:
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✅ Payment recorded!├── New Total Paid: $1,200.00├── New Balance: $0.00├── Status Changed: Partial → PAID└── New payment row added to transaction history
Transaction History
Each payment creates a record in institutionkit_transactions:
| Column | Description |
|---|---|
transaction_id | Auto-increment |
invoice_id | Linked invoice |
amount | Payment amount |
payment_method | Cash, Bank Transfer, Credit Card, Check |
payment_date | Date of payment |
notes | Optional notes |
recorded_by | Admin who recorded it |
created_at | Timestamp |
Article 21: PDF Invoice Generation
Apprentice Lesson Setup
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Chapter: Fee & Invoice SystemLesson Title: "Generating Professional PDF Invoices"Lesson Type: Feature GuideLabels: [Admin] [Accountant] [Guide]
Article Content
Last Updated: 2026-05-27 | Applies to: IK v1.2+
PDF Download Options
From Invoice List:
Click "View" → "📄 Download PDF"
Direct URL:
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admin.php?page=ik-invoices&view=single&invoice_id=1045&ik_pdf=1
PDF Design Features
The PDF invoice includes:
Header Bar:
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SCHOOL NAME | ADDRESS | TEL: PHONE
Three-Column Header:
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FEE INVOICE [LOGO] #01045School Name UNPAIDSchool Address
Bill To Section:
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┌──────────────────┬──────────────────┐│ BILL TO │ INVOICE DETAILS ││ Student: John Doe│ Invoice: #01045 ││ Class: Grade 5 │ Title: May 2026 ││ Roll No: 1042 │ Issued: 01 May ││ Guardian: Mr. Doe│ Due: 10 May 2026 │└──────────────────┴──────────────────┘
Amount Cards:
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┌────────────┬────────────┬────────────┐│ TOTAL │ PAID │ BALANCE ││ Rs 1,200 │ Rs 600 │ Rs 600 │└────────────┴────────────┴────────────┘
Fee Breakdown Table:
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# Fee Item Amount (Rs)1 May Tuition Fee 5002 May Transport Fee 1003 Outstanding April Fee 5004 Outstanding March Fee 100───────────────────────────────────────── Total Rs 1,200
Footer:
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Terms: Please pay by due date to avoid late fees.This is a computer-generated invoice.Generated on May 27, 2026 | School Name © 2026
PDF Technical Details
Library: Dompdf (included at
includes/lib/dompdf/)Paper Size: A4 Portrait
Font: DejaVu Sans (Unicode support)
Logo:
assets/images/logo1.png(auto-detected)Fallback: 🏫 emoji if no logo found
Customizing the PDF
Change Logo:Replace assets/images/logo1.png with your school logo (PNG format, ~200px wide recommended)
Change Colors:The PDF uses a blue theme (#1e40af). To customize, modify the CSS in generate_invoice_pdf_raw() method.
Add Custom Fields:Edit the "Bill To" section in the PDF generation code.
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