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Invoice Module

Sales invoice generation, tax invoices, and customer billing.

📊 Overview​

The Invoice Module handles:

  • Sales Invoices - Customer billing
  • Tax Invoices - VAT compliance
  • Invoice Templates - Professional formatting
  • Payment Tracking - Collection management
  • Credit Notes - Returns and refunds
  • Recurring Invoices - Subscription billing

📝 Creating Sales Invoice​

Access: Invoice → New Invoice

Manual Invoice Creation​

Step 1: Customer Selection

  1. Click Select Customer
  2. Search by name/phone
  3. Or create new customer:
    • Name
    • Phone
    • Email
    • Address
    • Tax ID (for tax invoice)

Step 2: Invoice Header

Invoice #: Auto-generated (or manual)
Date: Transaction date
Due Date: Payment deadline
Reference: PO #, order #
Payment Terms: Net 30, COD, etc.

Step 3: Add Products

  1. Click Add Line Item
  2. Select product or type description
  3. Enter:
    • Quantity
    • Unit price
    • Discount (if any)
    • Tax rate

Line Item Shows:

  • Product name
  • Quantity × Unit price
  • Discount (%)
  • Subtotal
  • Tax amount
  • Line total

Step 4: Invoice Calculations

Subtotal:          ฿10,000.00
Discount:          -฿500.00 (5%)
                   -----------
Before Tax:        ฿9,500.00
VAT (7%):          ฿665.00
                   -----------
Total Amount:      ฿10,165.00

Step 5: Additional Options

  • Shipping Charge: Add if applicable
  • Payment Received: Mark if paid immediately
  • Notes: Special instructions
  • Attachments: Supporting documents

Step 6: Save & Actions

  • Save Draft: Save without finalizing
  • Save & Print: Generate PDF
  • Save & Email: Send to customer
  • Save & Mark Paid: If received payment

🧾 Invoice from POS​

Access: Restaurant → GUI Menu (POS)

Converting Order to Invoice​

After Order Complete:

  1. Order shows in completed orders
  2. Click order
  3. Click Generate Invoice
  4. System creates invoice:
    • Customer from order
    • Items from order
    • Payments recorded
    • Auto-numbered

Benefits:

  • Faster than manual entry
  • No errors
  • Automatic calculations
  • Payment already recorded

🧾 Tax Invoice​

When Required:

  • Customer requests tax invoice
  • VAT-registered customer
  • Government sales
  • Export documentation

Creating Tax Invoice​

Requirements:

  1. Customer Tax ID: Must have valid tax number
  2. Complete Address: Full customer address
  3. Tax Rate: Applied correctly (usually 7%)
  4. Item Details: Detailed description
  5. Sequential Numbering: No gaps in invoice numbers

Format:

TAX INVOICE

Seller:
Lucky CI4 POS & ERP
123 Main Street
Bangkok 10200
Tax ID: 0123456789012

Buyer:
ABC Company Limited
456 Business Road
Bangkok 10300
Tax ID: 9876543210123

Invoice #: TI-2025-001234
Date: December 13, 2025

Items:
Product A    10 units @ ฿100    ฿1,000.00
Product B    5 units @ ฿200     ฿1,000.00
                                ----------
Subtotal:                       ฿2,000.00
VAT 7%:                         ฿140.00
                                ----------
Total:                          ฿2,140.00

Payment Method: Bank Transfer
Payment Status: Paid

📄 Invoice Templates​

Access: Invoice → Templates

Default Template​

Included Sections:

  • Company logo
  • Company details
  • Invoice # and date
  • Customer information
  • Items table
  • Subtotal, tax, total
  • Payment terms
  • Bank details (if applicable)
  • Thank you message

Custom Templates​

Create Custom:

  1. Go to Templates
  2. Click Add Template
  3. Design:
    • Upload logo
    • Choose colors
    • Select font
    • Add/remove fields
    • Customize footer
  4. Save template
  5. Set as default or select per invoice

Template Types:

  • Standard Invoice
  • Tax Invoice
  • Pro Forma Invoice
  • Receipt
  • Credit Note
  • Quotation

💳 Payment Recording​

Recording Payment​

When Customer Pays:

  1. Open invoice
  2. Click Record Payment
  3. Enter:
    • Payment date
    • Amount paid
    • Payment method:
      • Cash
      • Bank transfer
      • Credit card
      • Check
    • Reference # (check #, transfer #)
    • Bank account (if transfer)

Partial Payments:

  • Record amount paid
  • Invoice remains "Partially Paid"
  • Balance due shown
  • Can record multiple payments

Example:

Invoice Total: ฿10,000

Payment 1:
Date: Dec 1
Amount: ฿5,000
Method: Bank Transfer
Status: Partially Paid
Balance: ฿5,000

Payment 2:
Date: Dec 15
Amount: ฿5,000
Method: Cash
Status: Fully Paid
Balance: ฿0

🔁 Credit Notes​

Access: Invoice → Credit Notes

When to Issue Credit Note​

Scenarios:

  • Customer returns products
  • Pricing error
  • Quality issue refund
  • Goodwill credit
  • Invoice cancellation

Creating Credit Note​

Step 1: Select Original Invoice

  1. Find invoice to credit
  2. Click Create Credit Note
  3. System copies invoice details

Step 2: Specify Items

  • Select items to credit
  • Enter quantities to refund
  • Adjust amounts if partial

Step 3: Reason

  • Return reason dropdown
  • Additional notes
  • Reference # (RMA, ticket #)

Step 4: Credit Amount

Original Invoice: ฿10,000
Credit Amount: ฿2,000
Net Amount: ฿8,000

Step 5: Accounting

  • Reduces customer balance
  • Adjusts inventory (if return)
  • Records in financial accounts

Status Options:

  • Applied to Invoice: Reduces amount owed
  • Refunded: Cash returned
  • Credit Balance: Held for future orders

🔄 Recurring Invoices​

Access: Invoice → Recurring

Setting Up Recurring Invoice​

For Subscriptions/Regular Customers:

Step 1: Create Template

  1. Set up invoice as usual
  2. Select Make Recurring

Step 2: Recurrence Schedule

  • Frequency:
    • Daily
    • Weekly
    • Monthly
    • Quarterly
    • Yearly
  • Start Date
  • End Date or Never expires
  • Generate X days before due date

Step 3: Automatic Actions

  • Auto-generate invoice
  • Auto-send email
  • Auto-mark overdue
  • Auto-send reminders

Example Use Cases:

  • Monthly rent
  • Subscription services
  • Retainer fees
  • Maintenance contracts

📊 Invoice Dashboard​

Access: Invoice → Dashboard

Key Metrics​

Overview Cards:

  • Total Invoiced: ฿1.2M (this month)
  • Paid: ฿950K (79%)
  • Unpaid: ฿250K (21%)
  • Overdue: ฿50K (4%)

Aging Report​

Outstanding by Age:

Current (0-30 days):    ฿150,000
31-60 days:             ฿75,000
61-90 days:             ฿15,000
90+ days (overdue):     ฿10,000
Total Receivable:       ฿250,000

Recent Invoices​

List Shows:

  • Invoice #
  • Customer name
  • Date
  • Amount
  • Status (Paid/Unpaid/Overdue)
  • Actions (View/Email/Record Payment)

📤 Sending Invoices​

Email Invoice​

Single Invoice:

  1. Open invoice
  2. Click Email
  3. Verify recipient
  4. Customize subject/message
  5. Attach PDF
  6. Send

Email Template:

Subject: Invoice INV-001234 from [Company]

Dear [Customer Name],

Please find attached invoice INV-001234 dated December 13, 2025.

Amount Due: ฿10,165.00
Due Date: January 12, 2026

Payment can be made via:
- Bank Transfer: Account # 123-456-789
- Cash at store
- Credit Card (in person)

Thank you for your business!

[Your Company]

Bulk Email​

Multiple Invoices:

  1. Go to invoice list
  2. Filter unpaid invoices
  3. Select invoices
  4. Click Bulk Email
  5. Confirm recipients
  6. Send

🔔 Payment Reminders​

Access: Invoice → Reminders

Automatic Reminders​

Configure:

  1. Enable auto-reminders
  2. Set rules:
    • 7 days before due: Friendly reminder
    • On due date: Payment due today
    • 7 days overdue: First overdue notice
    • 14 days overdue: Second notice
    • 30 days overdue: Final notice

Reminder Template:

Subject: Friendly Reminder - Invoice INV-001234

Dear [Customer],

This is a friendly reminder that invoice INV-001234 
for ฿10,165.00 is due on January 12, 2026.

Please disregard this notice if payment has already 
been made.

View Invoice: [Link]
Make Payment: [Payment Link]

Thank you,
[Company]

Manual Reminders​

Send Individual Reminder:

  1. Open overdue invoice
  2. Click Send Reminder
  3. Edit template if needed
  4. Send

🔍 Invoice Search & Filters​

Access: Invoice → View All

Search Options​

Search By:

  • Invoice number
  • Customer name
  • Date range
  • Amount range
  • Status
  • Payment method

Filter Examples​

Overdue Invoices:

  • Status: Unpaid
  • Due date: Before today
  • Sort by: Days overdue

Large Invoices:

  • Amount: > ฿50,000
  • Status: Any
  • Sort by: Amount descending

Customer Invoices:

  • Customer: Select specific
  • Date: Year to date
  • Sort by: Date descending

📋 Invoice Management​

Editing Invoices​

Draft Invoices:

  • Can edit freely
  • Change items, amounts
  • Update customer details

Finalized Unpaid Invoices:

  • Limited editing
  • Can update notes
  • Can change due date
  • Cannot change amounts

Paid Invoices:

  • Cannot edit
  • Create credit note if needed
  • Or reverse payment and recreate

Deleting Invoices​

Can Delete:

  • Draft invoices
  • Same day (if configured)
  • No payments recorded

Cannot Delete:

  • Paid invoices
  • Referenced in reports
  • Closed periods

Instead: Issue credit note

Voiding Invoices​

Void Invoice:

  1. Open invoice
  2. Click Void
  3. Enter reason
  4. Confirm

Effect:

  • Status changes to "Void"
  • Doesn't count in reports
  • Keeps invoice number (no gaps)
  • Customer balance not affected

💼 Customer Statements​

Access: Invoice → Customer Statement

Generate Statement​

Step 1: Select Parameters

  • Customer
  • Date range
  • Include: Invoices/Payments/Credits

Step 2: Statement Shows

CUSTOMER STATEMENT
ABC Company Limited
Period: November 1 - December 31, 2025

Date       | Type    | Reference | Debit     | Credit    | Balance
-----------|---------|-----------|-----------|-----------|----------
Nov 1      | Balance |           |           |           | 5,000.00
Nov 5      | Invoice | INV-1234  | 10,000.00 |           | 15,000.00
Nov 10     | Payment | PAY-567   |           | 10,000.00 | 5,000.00
Nov 15     | Invoice | INV-1235  | 8,000.00  |           | 13,000.00
Nov 20     | Credit  | CN-789    |           | 1,000.00  | 12,000.00
           |         |           |           |           |
           | Closing Balance     |           |           | 12,000.00

Step 3: Actions

  • Print statement
  • Email to customer
  • Export to PDF

⚙️ Invoice Settings​

Access: Settings → Invoice

General Settings​

Invoice Numbering:

  • Prefix (INV-, SI-)
  • Starting number
  • Auto-increment
  • Reset: Never/Yearly/Monthly

Default Values:

  • Payment terms (Net 30)
  • Tax rate
  • Currency
  • Notes/footer

Email Settings​

SMTP Configuration:

  • Email sender name
  • Reply-to address
  • Email signature
  • Attach PDF automatically

Taxation​

Tax Configuration:

  • Enable VAT
  • Tax rate (%)
  • Tax-inclusive pricing
  • Tax ID display
  • Tax rounding

📊 Invoice Reports​

Access: Reports → Invoice

Available Reports​

Invoice Summary:

  • Total invoiced
  • By status
  • By customer
  • By period

Sales Analysis:

  • Revenue trends
  • Top customers
  • Payment methods
  • Average invoice value

Collection Report:

  • Days to collect (average)
  • Collection rate
  • Overdue rate
  • Bad debt

Customer Aging:

  • Outstanding by customer
  • Aging brackets
  • Collection priority

🎯 Best Practices​

Professional Invoicing​

✅ DO:

  • Send immediately after service
  • Include all required information
  • Use professional templates
  • Clear payment terms
  • Multiple payment options
  • Send reminders promptly

❌ DON'T:

  • Delay invoice creation
  • Use generic descriptions
  • Forget tax ID (for tax invoices)
  • Skip sequential numbering
  • Ignore overdue invoices

Collection Management​

Proactive Steps:

  1. Send invoice promptly
  2. Reminder before due date
  3. Follow up on due date
  4. Escalate if overdue
  5. Maintain communication
  6. Offer payment plans if needed

🔍 Troubleshooting​

Invoice Won't Save​

Check:

  • All required fields filled
  • Customer selected
  • At least one line item
  • Positive amounts
  • Valid dates
  • Tax calculations correct

Email Not Sending​

Verify:

  • Customer email valid
  • Email settings configured
  • Internet connection
  • PDF generating successfully
  • Not in spam folder

Payment Not Recording​

Ensure:

  • Correct invoice selected
  • Payment amount valid
  • Date not in future
  • Payment account selected
  • User has permission

Professional invoicing ensures timely payment and happy customers! 💼✨