How to Create a 100% GST-Compliant Tax Invoice in India

⏱️ Estimated time: 2 minutes•Level: Beginner•Updated for FY 2026-27

Under Section 31 of the CGST Act, every registered business must issue a tax invoice containing specific mandatory fields to enable buyers to claim Input Tax Credit (ITC). Here is how to create a flawless GST invoice in under 2 minutes.

What you will need before starting:

Active GSTIN (15-digit number)
Recipient GSTIN or State Code (for B2B)
HSN / SAC code for goods or services

Step-by-step instructions

Enter Consecutive Invoice Numbering

Rule 46(b) of CGST Rules mandates a consecutive serial number unique for a financial year, containing only letters, numbers, and hyphens/slashes (maximum 16 characters). VoyceBook auto-increments this according to your prefix (e.g., VB/26-27/001).

Pro Tip: Never reuse an invoice number across financial years.

Select Recipient & Verify Place of Supply

Input your client's registered business name and 15-digit GSTIN. If the first two digits match your GSTIN's state code, VoyceBook auto-splits tax into CGST + SGST (e.g., 9% + 9%). If the state differs, IGST (18%) is applied.

Pro Tip: VoyceBook validates the buyer's GSTIN against government databases in real time to prevent invalid ITC claims.

Add Line Items with Correct SAC/HSN Codes

Specify service or product descriptions with standard 6-digit SAC codes (e.g., 998314 for IT consulting) or HSN codes. Set quantity, unit rate, and select the applicable GST tax bracket (0%, 5%, 12%, 18%, or 28%).

Pro Tip: Services require a 6-digit SAC code starting with '99'.

Attach Bank Details & UPI Payment QR Code

Include your bank account number, IFSC code, and registered UPI VPA so buyers can pay directly. VoyceBook embeds a dynamic BharatQR / UPI QR code on the PDF.

Pro Tip: Invoices featuring direct UPI QR codes are paid 35% faster on average.

Dispatch via WhatsApp and Email in 1 Click

Hit send to deliver the PDF directly to the client's WhatsApp and inbox with a secure online payment link. VoyceBook notifies you the moment the client views the invoice.

Best practices & compliance notes

Always include reverse charge mechanism (RCM) declaration if billing advocate services or sponsorship.

Specify payment terms explicitly (e.g., 'Due within 15 days') to trigger MSME Section 43B(h) protections.

Got questions?

Frequently Asked Questions

What is the maximum character limit for a GST invoice number in India?

Under Rule 46 of the CGST Rules, an invoice number cannot exceed 16 alphanumeric characters, including slashes and dashes.

When is an e-invoice with IRN mandatory?

E-invoicing with Invoice Reference Number (IRN) generated via government IRP is mandatory for businesses whose aggregate turnover exceeded ₹5 Crore in any preceding financial year since 2017-18.

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How to Reconcile GSTR-2B Input Tax Credit Without Missing Deadlines →

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