The GST invoice checklist I wish every freelancer used

A designer I know sent a beautiful invoice last month. The client’s accounts team sent it back the same day. Not because the design was bad, but because it called itself a “GST invoice” without a GSTIN, place of supply, or SAC. The work was fine. The paperwork wasn’t.

An invoice is a legal document with a design layer on top. Here’s the checklist I’d tape to a monitor.

First, name the document correctly

If you’re not registered under GST, don’t charge GST and don’t issue a tax invoice. You can issue a normal invoice or bill of supply depending on your situation. Get this wrong and you’re collecting a tax you can’t remit.

The fields that get checked

1. Your legal name and registered address.
2. Your GSTIN, displayed correctly.
3. A consecutive invoice number and the invoice date.
4. The client’s legal name and address; their GSTIN if they are registered.
5. The place of supply, with the state code where your template supports it.
6. The SAC for services or HSN for goods.
7. A clear description of what was supplied.
8. Quantity and unit — for many services, a quantity of 1 with a clear description is enough.
9. Taxable value before tax, and any discount shown separately.
10. The GST rate and amount, split into CGST and SGST or shown as IGST.
11. A reverse-charge declaration where it applies.
12. Your signature or digital signature, with designation where required.

Place of supply decides the tax split

For most B2B services, the place of supply is the recipient’s location. If you’re in Karnataka and your client is in Maharashtra, that’s an inter-state supply and IGST applies. If both are in Karnataka, CGST and SGST apply. Get the state and GSTIN right before you choose the tax heads.

There are exceptions — immovable property, events, transport, and financial services, for example. If your work crosses those lines, ask a tax professional. A template won’t save you from a wrong place-of-supply rule.

Invoice numbering that survives scrutiny

• Use a distinct series per financial year or business vertical, and keep it consecutive.
• Don’t reuse a number after cancellation. Mark the invoice cancelled and retain it.
• If branches or terminals issue invoices, distinguish their series clearly.
• Retain records for the period required by GST law — commonly described as 72 months from the annual return due date. Confirm the current requirement for your business.
• Keep the PDF, the payment proof, and the ledger entry together.

GST rates changed. Your template probably didn’t.

The September 2025 rate rationalisation moved a lot of goods and services. Plenty of freelancers are still using a 2022 template with 12% and 28% options. Check the current notification for your service; don’t copy the rate from an old invoice.

Most B2B professional services sit at 18%, but “most” isn’t “all”. Restaurant services, construction, transport, and exports have their own rules. When in doubt, ask your CA and write the answer down for the next invoice.

Exports and LUT

If you export services, you generally don’t charge IGST. You may export under a letter of undertaking (LUT), or pay IGST and claim a refund. The invoice needs the export-specific details and should reference the LUT where applicable. Keep the payment evidence — FIRC, FIRA, or bank credit advice — with the invoice.

E-invoicing: check whether it applies

E-invoicing applies to registered businesses above the turnover threshold when supplying B2B. In 2026 the commonly cited threshold is ₹5 crore aggregate turnover, but thresholds move. Verify on the e-invoice portal before assuming you’re exempt. If you are covered, the IRP-generated invoice and QR become part of the document.

TDS, advances, and client portals

• TDS is deducted by the client at payment. Don’t reduce the invoice value to “account for” it.
• Advances for services may need a receipt voucher and a later adjustment. Ask your CA how to handle them.
• Purchase orders often demand a vendor code, cost centre, and PO number. Add those fields to your template from day one.
• If you invoice in a foreign currency, show the currency, the exchange rate used, and the INR equivalent where your records need it.

A pre-send checklist

• The document type matches the supply and your registration.
• Your GSTIN is active and correctly formatted.
• The invoice number is unique and in sequence.
• The invoice date and place of supply are correct.
• The client’s legal name and GSTIN match their records.
• The SAC or HSN matches the work.
• The description is specific enough to defend.
• The taxable value and discount are clear.
• CGST/SGST or IGST is correct, and the totals add up.
• Reverse charge is declared where applicable.
• The signature, bank details, and UPI link are present.
• The PDF filename is professional and searchable.

Use a tool, then keep a copy

Invoice Studio calculates CGST, SGST, and IGST, supports tax invoices, quotations, and export invoices, and exports a PDF without a login. Your data stays in the browser, which is good for privacy and bad for accidental device loss. Download the PDF, save it to your books, and back up the source file.

A tool removes arithmetic mistakes. It doesn’t remove the need to understand the fields. The best invoice software in the world can’t fix a wrong place of supply.

The five-minute monthly habit

Once a month, open your invoice folder and check four things: sequence gaps, unpaid invoices, GST totals against your GSTR-1, and client GSTINs that changed. Five minutes beats a panicked email in March.

Boring is the goal

A good invoice is boring in the right way. The client’s accounts team can match it, your CA can reconcile it, and you can explain every field without opening a browser tab. Design the template once, check the current rules, and then spend your energy on the work.