e-Invoicing in India 2026: Who Must Do It and How IRN Works

e-Invoicing does not mean emailing a PDF. It means reporting your invoice to a government portal before you give it to the customer, and receiving a unique number back.

Who has to do it

The threshold has fallen steadily since 2020. Businesses with annual aggregate turnover above ₹5 crore must generate e-invoices for B2B supplies. Turnover is calculated PAN-wide, not per GSTIN, and once you cross the limit in any year you stay in the system permanently.

e-Invoicing applies to B2B, SEZ, deemed export and export invoices. Plain B2C sales are outside it.

How the IRN process works

1. You create the invoice in your billing software as usual.
2. The software sends it in the government's schema to the Invoice Registration Portal.
3. The IRP validates it, checks for duplicates, and returns an IRN — a 64-character hash — plus a digitally signed QR code.
4. You print the IRN and QR code on the invoice before handing it over.

Without a valid IRN, a B2B invoice from a covered business is not legally valid, and your buyer cannot claim input credit.

The 30-day reporting rule

Invoices must be reported to the IRP within 30 days of the invoice date. Miss the window and the portal simply rejects the invoice — there is no appeal, and you are left with a document your customer cannot claim credit against.

Cancelling an IRN

You can cancel an IRN within 24 hours of generating it, and only in full — partial cancellation does not exist. After 24 hours, your only route is a credit note against the original invoice.

What e-invoicing gives you back

The compliance burden comes with a real benefit: reported invoices flow automatically into your GSTR-1 and into your buyer's GSTR-2B. Done properly, it removes most reconciliation work at month end.