GST & tax
How to create a GST invoice
A GST tax invoice is not a design exercise: it is a document with a required field list. Get the fields, the numbering and the tax split right and a simple PDF is perfectly valid.
Below is what each invoice must carry, how to number your series, and the difference between a tax invoice and a bill of supply.
Mandatory fields on a tax invoice
| Field | What to enter |
|---|---|
| Supplier details | Your legal name, address and GSTIN |
| Invoice number | Consecutive series for the financial year, max 16 characters |
| Invoice date | Date of issue; add due date if you offer credit |
| Customer details | Name, address, and GSTIN if registered |
| Place of supply | State of supply: decides CGST/SGST vs IGST |
| Item description | What you sold, with HSN code for goods or SAC for services |
| Quantity and rate | Units and price per unit, plus any discount |
| Taxable value | Line value after discount, before tax |
| Tax | Rate and amount of CGST and SGST, or of IGST |
| Total | Grand total, usually rounded to the nearest rupee |
| Signature | Signature or digital signature of the supplier or authorised person |
Not sure what the HSN or SAC code on that line item actually means, or how many digits yours needs? See what are HSN and SAC codes.
Step by step
- Enter your business details once: name, address, GSTIN, logo and bank or UPI details.
- Add the customer, including GSTIN for a B2B sale so they can claim input credit.
- Set the invoice number from your series and the invoice date, then pick the place of supply.
- Add each line: description, HSN or SAC, quantity, rate, discount and the GST rate for that item.
- Check that the tax appears as CGST + SGST for a local sale or IGST for an inter-state sale, then confirm the rounded total.
- Download the PDF, print it, or share it with the customer.
The GST invoice generator follows exactly these steps and can save your business and customer details on your device so the next invoice takes under a minute.
Numbering your invoice series
Numbering is where small businesses most often slip. Keep one unbroken series per financial year and never reissue a number. If an invoice is wrong, issue a credit note rather than editing or deleting the original.
- INV/2025-26/001: year-scoped, easy to audit.
- KD-0001: simple prefix with a running counter.
- Avoid restarting at 001 mid-year, or maintaining several overlapping series casually.
Tax invoice vs bill of supply
| Situation | Document | Shows GST? |
|---|---|---|
| Registered, taxable supply | Tax invoice | Yes |
| Exempt or nil-rated supply | Bill of supply | No |
| Composition scheme dealer | Bill of supply | No |
| Not registered under GST | Invoice without GST | No |
Working out the tax first? Use the GST calculator or read how to calculate GST.