E-invoicing does not mean simply emailing a PDF invoice. Under GST, it means reporting each eligible invoice to a government system, which validates it and returns a unique number. If you are covered and you skip it, your invoice is not valid. This guide explains e-invoicing under GST.

Who must issue e-invoices?

E-invoicing is compulsory for registered businesses whose aggregate turnover exceeded ₹5 crore in any financial year from 2017-18 onwards. This limit has applied since 1 August 2023. Turnover is counted across all registrations under the same PAN.

Who is exempt

Some categories are exempt regardless of turnover, including:

  • Special Economic Zone units
  • Insurance companies, banking companies and financial institutions, including NBFCs
  • Goods transport agencies and passenger transport services
  • Admission to cinema halls (multiplex screens)
  • Government departments and local authorities

Which documents are covered?

  • Tax invoices for supplies to registered persons (B2B)
  • Exports, and supplies to SEZ units and developers
  • Credit notes and debit notes for these supplies
  • From 1 January 2027, reverse charge self-invoices for supplies from unregistered persons and for import of services

Supplies to consumers (B2C) are outside e-invoicing.

How it works

  1. Create the invoice in your accounting or billing software in the standard e-invoice format.
  2. Report it to an Invoice Registration Portal (IRP), directly, through your software, or through a service provider.
  3. Get the IRN and QR code. The IRP validates the invoice, generates an Invoice Reference Number (IRN), digitally signs it and returns a QR code.
  4. Issue the invoice to your customer with the QR code printed on it.
  5. Automatic flow. The data flows into your GSTR-1 and, where needed, into the e-way bill system.

The 30-day reporting rule

Businesses with aggregate annual turnover of ₹10 crore or more cannot report an invoice, credit note or debit note to the IRP more than 30 days after its date. This has applied since 1 April 2025. If you miss the window, the portal will not generate an IRN, and the invoice cannot be validly issued. Businesses below ₹10 crore are not covered by this limit, but should still report promptly.

Common errors

  • Not starting on time after crossing ₹5 crore, leaving invoices invalid
  • Wrong buyer GSTIN or place of supply, which causes rejection or wrong credit
  • Duplicate invoice numbers in the same financial year
  • Wrong HSN codes or units of measurement
  • Missing the 30-day limit for larger businesses
  • Cancelling after 24 hours, which is not allowed; issue a credit note instead
  • Issuing a PDF without the QR code, which the buyer cannot rely on

Why it matters for your buyers

Your business customers claim input tax credit based on invoices reported in their GSTR-2B. If your e-invoice is invalid or missing, their credit is at risk, and they may hold back payment. Read about input tax credit and the GSTR-1 and GSTR-3B cycle.

Our e-invoice and e-way bill team sets up compliant invoicing, checks your applicability and helps your accounts team avoid rejections.

This article explains the general GST position as on the date shown. E-invoicing rules and portal requirements change through notifications and advisories; confirm the current position before acting.