GST & e-Invoice — GSTR-1/3B/2B, IRN & e-way bill

The three returns, in one minute

GST has a few moving parts, but for most businesses it comes down to three documents. Once you see how they relate, the whole thing feels manageable.

Filing GSTR-1 (what the groups mean)

When you open GSTR-1, your invoices are already grouped for you. Here's what each group is, so the summary makes sense.

• B2B — sales to GST-registered businesses (their GSTIN is on the invoice).
• B2C — sales to end customers (large inter-state ones are shown separately).
• CDNR — credit and debit notes against earlier sales (returns, adjustments).
• HSN summary — your sales totalled by product code, which the portal expects.
• Exports / nil-rated — shown separately where they apply.

GSTR-3B and actually paying your tax

GSTR-1 reports your sales in detail; GSTR-3B is the short monthly summary where you declare totals and pay. The number that matters is the net tax.

Net tax = the GST you collected on sales (output tax) minus the eligible GST you paid on purchases (input tax credit). Recording your purchase bills is what lets you reduce what you pay — skip them and you overpay.

Reconciling ITC with GSTR-2B

GSTR-2B is the government's record of the purchases your suppliers reported. To claim the right Input Tax Credit, you match your recorded purchase bills against it.

Anything in your books but missing from 2B usually means a supplier hasn't filed — chase them before you finalise, so you don't claim credit that isn't yet supported.

e-Invoice (IRN): who needs it and how

e-Invoicing means registering a B2B invoice on the government portal, which returns a unique IRN and a signed QR code. It becomes mandatory once your turnover crosses the notified threshold.

MGH Books prepares the e-invoice from your data so you don't re-type; the portal issues the IRN. This feature is on the Unnati plan and above, and needs your own portal eligibility and credentials.

e-Way bill: moving goods

An e-way bill is required to transport goods above a value threshold (generally ₹50,000, with state variations). It has two parts — invoice details (Part A) and transport details (Part B).

Generate it straight from the invoice in MGH Books: add the transporter or vehicle and distance, and the e-way number and QR attach to the bill.

Monthly or QRMP (quarterly)?

Your turnover decides whether you file monthly or can opt for the QRMP scheme (quarterly return, monthly payment).

How to avoid GST notices

• Keep GSTR-1, 3B and 2B consistent — built from one system, they reconcile by design.
• Keep invoice numbers sequential and unbroken.
• Set the correct place of supply so CGST/SGST vs IGST is right.
• File on time — late filing delays your buyers' ITC and adds fees.
• Keep HSN codes on items so the HSN summary is accurate.