Updated 17 October 2026 · By Ashok Sachdev
The question, as shop owners ask it: "My CA keeps calling at the end of every month asking for bills and reports. What exactly should I send so my GST returns are filed on time without the back and forth?"
Quick answer
Every month, send your CA eight things: the sales register (all bills), a list of B2B sales with each buyer's GSTIN, the HSN-wise sales summary, credit and debit notes, the invoice number ranges used and cancelled, the purchase register with supplier GSTINs plus the supplier bills, your expense bills that carry GST, and the bank and cash summary. Send them in the first week of the month, because GSTR-1 is due on the 11th and GSTR-3B on the 20th for monthly filers.
Most late fees and mismatches start with missing paper, not with the CA. If the monthly pack is complete and arrives early, the returns take minutes. Here is the checklist, why your CA needs each item, and how to get it out of your billing software in one go.
The monthly GST pack: what to send and why
| # | What to send | Why the CA needs it |
|---|---|---|
| 1 | Sales register: every bill with date, number, value and GST | Base for GSTR-1 and the output tax in GSTR-3B |
| 2 | B2B sales list with buyer GSTIN, invoice number, value and tax | GSTR-1 reports B2B invoices one by one so buyers get input tax credit |
| 3 | B2C sales summary by tax rate (and by state for sales to other states) | B2C sales go into GSTR-1 as totals |
| 4 | HSN-wise summary of sales | GSTR-1 has an HSN summary table |
| 5 | Credit and debit notes issued (returns, price changes) | They adjust the month's tax; reported in GSTR-1 |
| 6 | Invoice series used: first and last number, and cancelled bills | GSTR-1 document summary |
| 7 | Purchase register with supplier GSTIN, invoice number and tax, plus copies of supplier bills | Input tax credit, matched against your GSTR-2B |
| 8 | Expense bills with GST (rent, electricity where applicable, repairs, transport) and the bank and cash summary | Extra credit where allowed, and to tie payments to tax |
What GSTR-1 and GSTR-3B contain is explained in GSTR-1 vs GSTR-3B. How credit is matched: GSTR-2B reconciliation.
Monthly timeline for a shop filing monthly
| When | What happens |
|---|---|
| Last day of the month | Close the day as usual; enter any pending purchase bills |
| 1st to 5th | Export the reports and send the pack to the CA |
| By the 11th | CA files GSTR-1 (sales) |
| After GSTR-2B is available | CA matches supplier bills; you chase suppliers whose bills are missing |
| By the 20th | CA files GSTR-3B; you pay the net tax |
Shops with turnover up to ₹5 crore can choose the quarterly QRMP scheme, which changes the return dates but still needs monthly tax payment. Composition shops file CMP-08 every quarter instead. Late GSTR-3B costs a per-day late fee plus 18% interest on late tax: see GSTR-3B late fee and interest.
