Section 31 - Tax invoice.

Tax invoice obligations require issuance at supply or payment with special rules for revised invoices, bills, and vouchers.

A registered supplier of taxable goods must issue a tax invoice before or at removal or delivery, showing prescribed particulars; for taxable services a tax invoice must be issued before or after provision but within a prescribed period. The Government may notify categories where other documents are deemed tax invoices or where invoices need not be issued. Revised invoices, bills of supply for exempt or composition taxpayers, receipt vouchers for advance payments and refund vouchers where no supply occurs are mandated. Suppliers liable under section 9 must issue invoices on receipt and payment vouchers on payment; special timing rules apply to continuous supplies and approval sales.