What Must Be on a GST Invoice: B2B vs B2C Essentials
Published: 10/9/2026
Category: GST
A GST invoice missing a required detail can cost your customer their input tax credit and cost you their trust. The essential fields for B2B and B2C invoices, explained simply.
A GST tax invoice must carry specific details set out in the CGST Rules. For B2B invoices, missing or wrong details, especially the buyer's GSTIN or place of supply, can stop your customer from claiming input tax credit. For B2C invoices, fewer buyer details are needed, but the core seller, item and tax information is the same.
Fields on every tax invoice
| Field | Notes |
|---|
| Supplier's name, address and GSTIN | Exactly as registered |
| Invoice number | Unique within the financial year, in a consecutive series |
| Invoice date | Date of issue |
| Description of goods or services | Clear enough to identify what was supplied |
| HSN or SAC code | Number of digits depends on your turnover and the type of invoice |
| Quantity and unit | For goods |
| Value and taxable value | After discounts shown on the invoice |
| Tax rate and amount | CGST + SGST, or IGST |
| Place of supply | State name, especially for inter-state supplies |
| Signature or digital signature | Of the supplier or authorised person |
Extra details for B2B invoices
- Recipient's name, address and GSTIN
- Delivery address if different from the billing address
- Whether tax is payable on reverse charge
- IRN and QR code if you are required to issue e-invoices
B2C invoices
For sales to consumers, the recipient's GSTIN is not needed. For higher-value sales to unregistered buyers, the rules require the recipient's name and address (and state). Check the current value limit with your CA.
Common mistakes
- Typing the customer's GSTIN wrong
- Charging CGST + SGST on an inter-state sale (should be IGST)
- Missing or wrong HSN codes
- Duplicate or out-of-sequence invoice numbers
- Discounts given outside the invoice
Bill of supply
Composition dealers and suppliers of exempt goods or services issue a bill of supply instead of a tax invoice, without charging GST.
Where BizFlow fits
BizFlow generates GST invoices with every required field: saved customer GSTINs, automatic IGST or CGST + SGST from the place of supply, HSN codes from the item master and unique number series per financial year, plus e-invoice IRN and QR where applicable. See GST billing.
General information; confirm requirements with your CA.
Frequently asked questions
Q: Is the buyer's GSTIN mandatory on a GST invoice?
A: For B2B supplies to registered buyers, yes; without it they cannot claim input tax credit. It is not needed for B2C sales.
Q: How many digits of HSN code should I use?
A: It depends on your aggregate turnover and whether the invoice is B2B or B2C. Check the current notification with your CA.
Sources
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