GST Return requirements mandate invoice-level reporting, HSN/SAC coding, separate tables for adjustments and timely monthly filing obligations. GSTR-1 must capture taxpayer identity and period, invoice-level outward supply details for goods and services, place of supply, and reverse charge supplies. HSN and SAC coding obligations are tiered by turnover and transaction type, with higher granularity for larger taxpayers and for exports/imports; descriptions suffice where codes are not mandated. Separate tables must report advances, taxes on advances, exports, credit/debit notes, return corrections, and NIL/exempt/non GST supplies, and the return is filed monthly with late filing subject to fees.