Invoice documentation requirements under GST: sequential serialisation and mandatory particulars for tax invoices and vouchers.
GST documentation for GSTR returns mandates consecutively serialised documents and prescribed particulars. Tax invoices must record supplier and recipient identifiers, a unique serial number format, issue date, descriptions including HSN/Accounting codes, quantities, taxable and total values, tax rates and amounts, place and address of supply, reverse charge indication, and signature. Special documents-revised invoices, debit and credit notes, receipt and refund vouchers, payment vouchers, and delivery challans-must be serialised, reference corresponding original documents where applicable, contain specified particulars, and be declared in the appropriate return period, with delivery challans prepared in triplicate for transport. (AI Summary)

Reverse charge mechanism: exemption for intra state purchases from unregistered suppliers up to a daily threshold; exceeding threshold triggers recipient liability.
An exemption permits registered recipients to avoid central tax on intra state taxable supplies received from unregistered suppliers when the aggregate value of such supplies received in a single day from all unregistered suppliers does not exceed a specified daily threshold; if the aggregate exceeds the threshold the recipient is liable to pay tax on the total value, exempt supplies are excluded, interstate supplies and supplies under compulsory reverse charge are not covered, and input tax credit for tax paid under reverse charge is subject to payment and invoice rules. (AI Summary)