Which document do you need?
| Situation | Document | Rule |
|---|---|---|
| Taxable sale by a registered business | Tax invoice | Section 31, Rule 46 |
| Exempt supply, or a composition dealer selling | Bill of supply | Rule 49 |
| Quote or advance request before a sale | Proforma invoice | No GST rule (commercial) |
| Goods sent for job work, approval or between your godowns | Delivery challan | Rule 55 |
| Sale value or tax to be reduced, goods returned | Credit note | Section 34, Rule 53 |
| Sale value or tax to be increased | Debit note | Section 34, Rule 53 |
All four formats use the same layout: your details at the top, the other party, an items table with HSN, quantity and value, then tax and totals and a signature. That keeps your documents consistent with each other and with your returns.
One rule for every series
Invoices, credit notes and debit notes carry a consecutive serial number of up to 16 characters (letters, digits, hyphen and slash), unique for the financial year. Keep a separate series for each document type, and for proformas and challans too, so numbers never collide. Bills of supply follow the same numbering rule (Rule 49).
Copies, storage and signatures
Goods invoices are prepared in three copies (original for the recipient, duplicate for the transporter, triplicate for the supplier) and service invoices in two (Rule 48). Delivery challans also go in three copies under Rule 55(2). A paper document is signed by you or an authorised signatory; an electronic invoice issued under the IT Act does not need a signature. Keep your copies with your books of account: GST records are kept for at least 72 months from the due date of the annual return for the year (Section 36).
Paper, PDF or billing software
A printed format works for a handful of bills a month. Once you bill every day, the risks are repeated numbers, tax worked on the total instead of per line, and GSTINs typed wrong. Billing software numbers documents for you, checks GSTINs and HSN codes, and prepares GSTR-1 from the same bills, so your returns match what you printed.
Fill online instead
The GST invoice generator fills the tax invoice for you: CGST and SGST or IGST from the place of supply, amount in words, and a check that every Rule 46 field is there. It works in your browser and saves nothing on our servers.
Rules as read on 17-10-2026. Check with your CA before relying on them for a filing.
