How to generate an e-invoice (IRN) in India: a step-by-step guide

To generate an e-invoice in India, you create your invoice in the prescribed GST schema, send it to the Invoice Registration Portal (IRP), and the IRP validates it and returns a unique Invoice Reference Number (IRN) plus a signed QR code. In short: you don't print an IRN yourself — the government's IRP issues it after your invoice passes validation.

What "e-invoicing" actually means

A common misconception is that e-invoicing means emailing a PDF. It doesn't. Under GST, e-invoicing is the process of reporting a B2B invoice to the IRP in a standard format (the e-invoice schema) so it can be authenticated centrally. The IRP then returns:

• an IRN (a unique 64-character hash that identifies the invoice),
• a digitally signed QR code, and
• the signed invoice data.

Your printed/shared invoice must carry that IRN and QR code to be a valid e-invoice.

Who needs to do it

E-invoicing applies to GST-registered businesses above a turnover threshold as notified by the government, for B2B supplies (and exports). The threshold has been lowered in stages over time, so the right move is to check your current obligation against the latest CBIC/GST notification rather than assume a fixed figure. Certain categories (such as some exempt entities) are outside its scope.

If you're unsure whether you're covered, confirm with your CA or the official GST portal — eligibility is based on the notified turnover limit applied to your aggregate turnover.

Step-by-step: how an e-invoice is generated

1. Prepare the invoice in the e-invoice schema

Capture all mandatory fields — supplier and recipient GSTINs, invoice number and date, HSN/SAC codes, taxable value, and the CGST/SGST/IGST breakup. Good billing software builds this JSON for you from a normal invoice entry.

2. Upload (report) the invoice to the IRP

The structured invoice is sent to the IRP, either directly through the portal, via a GST Suvidha Provider (GSP), or through API-enabled software. This is the "reporting" step.

3. The IRP validates the data

The IRP checks the schema, GSTINs, and for duplicates. If anything is wrong — a malformed field, an invalid GSTIN, or a repeat — it rejects the request with an error so you can fix and resubmit.

4. The IRP generates the IRN and signs the invoice

Once validated, the IRP creates the unique IRN, digitally signs the invoice, and produces the QR code containing key invoice details. This is the moment the invoice becomes a legally valid e-invoice.

5. Receive and store the response

The signed invoice, IRN, and QR code come back to you. Your software stores them against the invoice. The data also flows into the GST system, which helps pre-populate parts of your returns and can support e-way bill generation.

6. Issue the e-invoice with IRN and QR code

Print or share the invoice with the IRN and QR code on it. That's what makes it compliant for your buyer and for the tax authorities.

Cancelling an e-invoice

If you need to cancel, an e-invoice can be cancelled on the IRP within the time window allowed by the system (cancellation is full, not partial — you can't edit an IRN; you cancel and reissue). After the allowed window, you handle corrections through credit/debit notes instead.

Practical tips

• Let software build the schema. Manual JSON is error-prone; integrated tools reduce rejections.
• Validate GSTINs before reporting to avoid the most common failure.
• Keep the IRN and QR code with the invoice in your records — they're your proof of authentication.
• Check the current threshold against the latest notification before assuming you're in or out of scope.

E-invoicing sounds heavy, but the flow is consistent: prepare in schema, report to the IRP, get back an IRN and QR code, and issue the invoice carrying both. Once your billing tool handles the schema and reporting, it becomes a routine, near-instant step.