GST invoice mandatory fields

The checklist

Also required where relevant: delivery address if different from the place of supply; whether tax is payable on reverse charge; and the signature or digital signature of the supplier or an authorised person.

HSN code digits

The number of HSN digits depends on your aggregate turnover in the previous year: 4 digits up to ₹5 crore and 6 digits above ₹5 crore, for B2B invoices. Many businesses print 6 or 8 digits anyway. The rule is set by notification and can change; check cbic-gst.gov.in. More in HSN and SAC codes explained.

Unregistered buyers

For an unregistered recipient, the invoice must carry the recipient's name and address and the delivery address, with state name and code, where the taxable value is ₹50,000 or more. For smaller amounts these are optional, though the state still matters for inter-state supplies. Details are in GST on sales to unregistered buyers.

Where the value is below ₹200 and the buyer is unregistered and does not ask for an invoice, a single consolidated invoice can be issued for the day's such sales.

Example: invoice body

A Delhi electrical goods dealer sells to a registered contractor in Delhi:

Invoice total ₹40,710. Rates shown are for illustration; use the current rate for each HSN.

Timing and copies

• Goods: issue the invoice before or at the time of removal or delivery.
• Services: within 30 days of supplying the service (45 days for certain financial sector suppliers).
• Copies for goods: three: original for recipient, duplicate for transporter, triplicate for supplier.
• Copies for services: two: original for recipient, duplicate for supplier.

Special cases

• Reverse charge supplies: state clearly that tax is payable on reverse charge, so the buyer does not expect GST on your bill.
• Exports: add the buyer's overseas address, port code where relevant and the LUT or IGST-payment line; see GST for exporters.
• Exempt or composition sales: issue a bill of supply instead of a tax invoice.
• Advances for services: issue a receipt voucher, and later the tax invoice adjusting it.
• Corrections: use a credit or debit note referring to the original invoice, never a second invoice with the same number.

Extra requirements for larger businesses

• E-invoicing: businesses above the notified turnover must report B2B invoices to the Invoice Registration Portal and print the IRN and QR code; see e-invoicing and IRN.
• Dynamic QR code on B2C invoices: required for businesses above a much higher turnover limit.

Thresholds are notified and have been lowered over time. This is general information, not tax advice.

Mistakes buyers complain about

• Buyer's GSTIN missing or wrong, so ITC does not appear in their GSTR-2B.
• Tax shown as a single 'GST 18%' amount without the CGST/SGST or IGST split.
• Invoice numbers restarting mid-year, or duplicated across two billing counters.
• Place of supply missing on an inter-state invoice.
• Rounding differences between line tax and total tax.

Invoices from Tally and Cashflow OS

TallyPrime prints these fields once company, party and item masters carry GSTIN, state, HSN and rates. When sales vouchers are created from Cashflow OS with writing back switched on, they are posted into Tally and GST is worked out from the item and the party's state; Tally validates each entry. Cashflow OS documents such as quotations and proforma invoices carry your logo, bank and UPI details, but the tax invoice of record is the Tally voucher.