E-Billing · Updated 12 October 2026

How E-Invoicing Works

From your bill to an IRN and a signed QR code, step by step

E-invoicing, often called e-billing, is how larger GST businesses make their B2B invoices legally valid. You still create the invoice in your own software. What changes is one extra step: the invoice is reported to a government Invoice Registration Portal (IRP), which checks it, registers it and sends back a unique Invoice Reference Number (IRN) and a digitally signed QR code.

It does not mean emailing a PDF, and it does not mean the government writes your invoice for you.

Who Has to Use It

Businesses whose aggregate turnover crossed ₹5 crore in any financial year since 2017-18. Once in, you stay in, even if turnover later falls.
It covers B2B invoices, exports, supplies to SEZs and deemed exports, and the credit and debit notes against them.
Sales to consumers (B2C) do not need an IRN.

The limit, and the talk of lowering it, are covered in E-Invoicing Limit in 2026.

Step by Step

Create the invoice as usual in your billing or accounting software, with the buyer’s GSTIN, HSN codes, values and tax.
Send it to an IRP. The software turns the invoice into the government’s standard e-invoice format (a JSON file) and sends it to the IRP directly, or you download the file and upload it on the e-invoice portal yourself.
The IRP checks it: that the GSTINs are valid, that the same invoice number has not already been registered this financial year, and that the required fields are filled in.
The IRP generates the IRN, a unique 64-character code worked out from your GSTIN, the document number, its type and the financial year.
The IRP signs the invoice and adds a QR code holding the key details: both GSTINs, invoice number and date, invoice value, the main HSN code and the IRN.
You print the QR code on the invoice you give the buyer. Anyone can scan it to check that the invoice was registered.
The data moves on by itself. The invoice flows into your GSTR-1, and if goods are being moved, Part A of the e-way bill can be generated from the IRN.

The Rules That Catch People Out

Rule	What It Means
24-hour cancellation	An IRN can be cancelled only within 24 hours of being generated, and only in full. After that, issue a credit note, which is itself reported to the IRP.
No editing on the IRP	A registered e-invoice cannot be amended on the portal. Corrections go through a credit or debit note, or an amendment in GSTR-1.
30-day reporting window	Since 1 April 2025, businesses with aggregate turnover of ₹10 crore or more must report each invoice within 30 days of its date. Later ones are refused.
One number, once	The same invoice number cannot be registered twice in a financial year, so keep one clean series.
E-way bill first	If an e-way bill was raised from the IRN, it has to be cancelled before the e-invoice can be.

Who Is Exempt

These businesses do not generate IRNs, whatever their turnover:

Units in a Special Economic Zone (SEZ)
Insurers, banks and financial institutions, including NBFCs
Goods transport agencies (GTA)
Passenger transport services
Cinemas, for admission to multiplex screens
Government departments and local authorities

And these documents never need one: bills to consumers (B2C), bills of supply, delivery challans, imports, and exempt or nil-rated supplies. Very large businesses (turnover above ₹500 crore) have a separate rule for B2C bills: a dynamic QR code the customer can scan to pay.

What If an IRN Is Missed?

An invoice that needed an IRN but does not have one is not a valid tax invoice. Your buyer cannot claim input tax credit on it, which is usually the first you hear about the problem. It can also attract a penalty of ₹10,000 or the tax involved, whichever is higher.

Getting Ready

Verify every customer GSTIN before you bill, not after
Put the right HSN or SAC code on every item, because the IRP checks them
Keep one unbroken invoice series per financial year
Register your GSTIN on the e-invoice portal and create API credentials for your software
Make sure whoever bills knows the 24-hour cancellation rule

How Billing Software Helps

E-invoicing is only as good as the invoice you send. Correct GSTINs, HSN codes and tax at the moment of billing are what make the IRN come back first time.

BharatBill.online registers your invoice with the IRP and gets the IRN and signed QR code, once you enter your own e-invoice portal credentials. Or download the JSON and upload it yourself.

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Sources

Please note: this article is general information for small businesses and is accurate to the best of our knowledge on 12 October 2026. GST rules change often. Please confirm the current position on the official e-invoice portal or with your tax adviser before acting on anything here.