How to Create a GST-Compliant Invoice (Step by Step)

A GST invoice is more than a bill — it's the legal document your customer uses to claim input tax credit, and the record you rely on at return time. Get a field wrong and the invoice can be challenged. The good news: the rules are clear, and once you know them, issuing a correct invoice takes a couple of minutes. Here's exactly how to do it.

1. Start with the right document title

A taxable supply needs a document clearly titled “Tax Invoice”. If you're registered under the composition scheme, or supplying exempt goods, you issue a Bill of Supply instead, because you can't charge GST. For a quote before the sale, use a proforma invoice — it is not a tax invoice and carries no tax liability.

2. Add supplier and recipient details

Every tax invoice must carry your business name, address and GSTIN, plus the customer's name and address. If the customer is registered, include their GSTIN too. For an unregistered customer where the invoice value crosses ₹50,000, you also record their name, address and the state.

3. Give it a unique number and date

Each invoice needs a consecutive serial number (unique for the financial year, up to 16 characters, letters, numbers, / and - allowed) and the date of issue. Don't skip or reuse numbers — the sequence is part of what makes your records auditable.

4. Describe what you're supplying

List each item or service with a clear description, the quantity and unit where relevant, and the taxable value. Goods and services also need the appropriate HSN or SAC code; how many digits you must show depends on your turnover. Getting descriptions right avoids disputes and makes returns easier.

5. Apply the correct GST — CGST/SGST or IGST

This is where most mistakes happen. The tax depends on the place of supply:

• Same state (intra-state): split the GST into CGST and SGST, half each. 18% becomes 9% CGST + 9% SGST.
• Different states (inter-state): charge the full rate as IGST.

If you're unsure which applies, our CGST vs SGST vs IGST guide walks through it, and the GST calculator does the split for you.

6. Show the totals and amount in words

Show the taxable value, the tax amount broken up by head (CGST/SGST or IGST), any round-off, and the final total. It's standard practice — and expected — to also state the total in words, e.g. “Rupees One Thousand One Hundred Eighty Only”.

7. Sign and share it

The invoice should carry the signature or digital signature of the supplier or an authorised person. Then send it — as a PDF, or share it on WhatsApp. Adding your UPI ID lets you print a payment QR right on the invoice so the customer can pay in seconds.

Do e-invoicing rules apply to you?

Above a turnover threshold, you must also generate an Invoice Reference Number (IRN) and signed QR through the e-invoicing system. See what e-invoicing is and who needs it to check whether it applies to your business.

The fastest way to do all of this

You don't have to remember every field. The free Billzora invoice generator lays them out for you, validates your GSTIN, applies the correct CGST/SGST or IGST from the place of supply, writes the amount in words, and lets you download the PDF or share on WhatsApp — no login required.