What is Tax Invoice?
A tax invoice is the formal bill that a GST-registered business issues when it makes a taxable supply. It is not just a request for payment. It is the legal record that tells the tax department what you supplied, to whom, on what date, at what value and with how much GST. Typical fields include your name, address and GSTIN, a unique serial number, the invoice date, the recipient's details, a description of the service, the SAC code, the taxable value, the tax rate and amount, and a signature.
Export invoices are tax invoices too. Export of services is a zero-rated supply, so if you export under an LUT you charge no IGST, but the invoice must still carry the wording "Supply meant for export under LUT without payment of IGST".
Why it matters for exporters
Your tax invoice is the starting point for almost every export compliance step. Each invoice becomes one row in Part 2B of the EDF, and the invoice date decides when the EDF is due: within 30 days from the end of the month in which the invoice was raised. The same date starts the 9-month clock for realising the money. If the invoice number, date or amount on the EDF does not match your books, the bank may come back with questions when it matches the payment in EDPMS.
Example
Nimbus Labs Pvt Ltd, a Pune software firm, raises tax invoice NL/26-27/041 on 14 October 2026 to a client in Texas for USD 6,000 under LUT. The invoice shows SAC 998314, zero IGST and the LUT wording. Nimbus lists this invoice in its October EDF, due by 30 November 2026. You can build a compliant export invoice with the free export invoice generator and a domestic one with the GST invoice tool.
Common confusion
A proforma invoice looks similar but is only an offer or a request for an advance. It carries no tax liability and should not be reported as the export invoice on the EDF. This is general information, not tax advice; check invoice rules with your CA.