GST return filing translates the books of account into the forms notified for the tax period — outward supplies in GSTR-1 or IFF, summary liability and credit in GSTR-3B, and annual consolidation in GSTR-9, with GSTR-9C where applicable. The figures must be reconcilable with invoices, e-way bills, e-invoices, and the electronic credit ledger.
Monthly or quarterly working papers list B2B, B2C, export, and nil-rated supplies, compare them with the sales register, and identify invoices that were reported late or amended. Input tax credit is taken only for invoices that appear in GSTR-2B and that satisfy the conditions of section 16, including possession of the invoice, receipt of goods or services, and tax having been paid. Reverse-charge liabilities are computed separately so that they are not missed in 3B.
Annual return work starts from the year’s monthly filings rather than from a fresh extraction. Differences between 3B, 1, books, and 2B are tabulated and explained. Where GSTR-9C is required, the reconciliation statement follows the same tables.
Keeping period-wise workings next to the filed JSON avoids reconstructing the year when a notice or refund application asks how a particular table was populated.