GST Invoice Checklist: The Fields Every Invoice Should Carry

The most common GST invoice mistake we see is not a wrong tax figure. It's a missing field: no customer GSTIN, no place of supply, a description too vague to classify. The invoice goes out, the customer's accountant sends it back, and you lose a week.

Below is a working checklist of fields a tax invoice generally carries. Treat it as a starting point. GST rules, thresholds and formats are updated from time to time, and what you must show depends on your registration type and what you sell. Your CA is the person who confirms the current requirement for your business.

Fields about you

• Your legal business name and address
• Your GSTIN
• A serial invoice number that is unique for the financial year
• The invoice date
• Your signature or authorised signatory name, where required

Keep the business name identical to what is on your registration. A trade name on the invoice and a legal name on the portal is a classic source of mismatches. On numbering, see invoice numbering rules for how to keep the sequence clean.

It also helps to print the invoice series in a fixed place on the page rather than hand-writing it. Handwritten numbers and corrections are what customers' accountants question first, and they are hard to defend later. If you issue invoices in several formats, such as a counter bill and a formal invoice, make sure each has all the required details, or decide with your CA which format applies to which sale.

Fields about the customer

• Customer's name and billing address
• Customer's GSTIN, if they are registered
• Delivery address, if different
• Place of supply (the state), because it decides whether the tax splits into central and state parts or is charged as one integrated tax

Ask for the customer's GSTIN once, at the first sale, and save it on their record. Asking again at every invoice is how wrong numbers get typed. If the customer is not registered, your CA can tell you what the invoice needs to show and when.

For customers you bill often, a short onboarding form helps: legal name, address, GSTIN, a billing contact and the email for invoices. Fill it once, store it, and every future invoice is right the first time. This is far cheaper than correcting invoices later, which can involve credit notes; see credit notes and sales returns explained.

Fields about what was sold

• Description of goods or services in words a reviewer can classify
• HSN code for goods or SAC code for services, as applicable to your turnover
• Quantity and unit
• Rate per unit and any discount
• Taxable value for each line
• Tax rate and tax amount, shown separately
• Total invoice value in figures, and in words

Tax rates change and differ by item. We won't list any here. Look them up on the official GST portal or ask your CA, and set them once against each product so you aren't choosing a rate under pressure while a customer waits.

Be careful with descriptions as well. Misc items or goods will not help anyone classify what was sold. A description like cotton bedsheet, double tells the reviewer what the product is, and makes picking the right code easier for you. When in doubt, ask your CA once and note the answer against the product so it carries into every later invoice.

Other fields people forget

Some invoices need a reverse charge indicator. Some need transport details. Round-off lines should be visible, not hidden in the total. If you issue invoices for a mix of exempt and taxable items, keep them clearly separated so the tax is not applied to the wrong line. None of these is hard, but all of them are easy to forget when you're busy.

Another quiet source of trouble is mixing documents. A quotation or challan does not replace a tax invoice, and a tax invoice should not be called a quotation. The differences are explained in invoice vs quotation vs delivery challan.

Where software helps, and where it doesn't

Billing software removes retyping. You save the customer's details and the item's tax setup once, and every invoice picks them up. Billy lets you keep customers, products and invoice records in one place with sequential numbering. What we do not claim is GST return filing or e-invoicing integration. If you need either, check with every tool you evaluate and with your CA.

A final habit: once a month, pull ten random invoices and run them against this checklist before your accountant does. It takes twenty minutes and finds the patterns. If a particular field keeps going missing, it usually means your template or your process needs a fix, and a small customisation can often handle that.