Customers and vendors with GSTIN

Your parties are the people you sell to (customers) and buy from (vendors). Their GSTIN and state decide the tax on every invoice and whether you can claim credit on what you buy.

B2B and B2C

A sale to a GST-registered buyer is B2B: their GSTIN goes on your invoice and they can claim credit for the tax. A sale to a consumer or an unregistered buyer is B2C. Both are reported in your GSTR-1, in different tables.

The buyer's state decides the tax

For goods that move, the place of supply is where the movement ends [IGST Act 2017, section 10(1)(a)]. If that is your own state, you charge CGST + SGST; if it is another state, you charge IGST. The first two digits of the buyer's GSTIN tell the software their state.

Vendor GSTIN and MSME status

You can claim input tax credit only on bills from registered vendors whose invoices appear in your GSTR-2B (lesson 6). If a vendor is a registered micro or small enterprise, a buyer must pay within the agreed date, and the agreed date cannot be more than 45 days from acceptance; with no written agreement, within 15 days [MSMED Act 2006, section 15].

Questions

What if my customer has no GSTIN?

Then the sale is B2C. Leave the GSTIN blank and enter the customer's state, because the state still decides CGST+SGST or IGST.

Reviewed: 7 Nov 2026. This is general information, not advice from a chartered accountant. Rates and rules change; check the source named in brackets.