GST Invoice Format for E-commerce Sellers: Complete Guide (2026)

You ship a ₹42,000 bulk order of office chairs to a customer who bought from your D2C website. Three days later, they email you asking for a "proper B2B tax invoice" so they can claim Input Tax Credit. You sent them a standard Shopify receipt. Now they are threatening to return the order unless you send a compliant GST invoice today.

If you sell online in India, you are going to face this.

Marketplaces like Amazon and Flipkart automatically generate GST invoices for your orders. But the moment you start your own website, sell wholesale, or transition to B2B, the legal responsibility of formatting that document falls entirely on you. Get it wrong, and you annoy your best buyers. Get it completely wrong, and the GST department fines you ₹10,000 per missing invoice.

Here is exactly what a GST invoice must look like, the rules you need to follow, and the mistakes that trap new sellers.

There Is No "Official" Visual Layout

Let us start with the good news. The government does not mandate a specific visual template. You do not have to use a government-issued PDF format.

Your invoice can be pink, it can have your logo in the middle, and it can use any font you want. The GST department only cares about the data. As long as your document contains the 16 mandatory fields required by Rule 46 of the CGST Rules, it is a valid tax invoice.

If you do not even have a GSTIN yet, stop right here. You cannot issue a tax invoice without one. Read our complete guide to GST registration to get your business registered first.

The 16 Mandatory Fields Every Invoice Needs

Whether you sell phone cases on Instagram or industrial machinery on Amazon Business, your invoice must clearly show these items.

Your Business Details

1. Your Legal Name: Exactly as it appears on your GST certificate. If your registered name is "Rahul Enterprises" but your brand is "SleepyBear," the invoice must say "Rahul Enterprises."
2. Your Registered Address: The principal place of business listed on your registration.
3. Your GSTIN: Your 15-digit Goods and Services Tax Identification Number.

The Invoice Identity

4. Invoice Number: This must be a consecutive, alphanumeric serial number, unique for a financial year, and no longer than 16 characters. For example, SB/26-27/0014.
5. Date of Issue: The date you generated the invoice, which must be on or before the day the product ships.

The Buyer's Details

6. Buyer's Name: The customer's billing name.
7. Buyer's Address: The billing address.
8. Shipping Address: The delivery address (if it differs from the billing address).
9. Buyer's GSTIN: Only mandatory if the buyer is a registered business asking for a B2B invoice.

The Product Details

10. Item Description: A clear description of the goods. "Cotton T-shirt" is fine. "Item 1" is not.
11. HSN Code: The Harmonised System of Nomenclature code for your product. You need 4 digits if your previous year's turnover was up to ₹5 crore, and 6 digits if it was above ₹5 crore. Use the HSN code finder if you are unsure of the right code for your product.
12. Quantity: Number of units sold.
13. Total Value: The gross value of the goods before tax and discounts.
14. Taxable Value: The amount on which tax is calculated (gross value minus discounts).

The Tax Breakdown

15. Rate and Amount of Tax: You cannot just write "18% GST." You must split it. If the buyer is in your state, show CGST at 9% and SGST at 9%. If the buyer is in another state, show IGST at 18%.
16. Signature: A physical signature of the authorised supplier, or a digital signature.

B2B vs B2C Invoices: The E-commerce Difference

This is the distinction that confuses most new sellers.

A B2C (Business to Consumer) sale is when you sell to an everyday person buying for personal use. They do not have a GSTIN. They do not care about Input Tax Credit. Your invoice must still show the tax breakdown, but you do not need their tax details.

A B2B (Business to Business) sale is when you sell to another registered business. They want to claim the GST they paid you as an Input Tax Credit (ITC) to offset their own tax liability.

For a B2B invoice to be valid, you must include the buyer's exact GSTIN. When you file your GSTR-1 by the 11th of the month, you must upload this B2B invoice against their GSTIN. If you fail to do this, the credit will not appear in their GSTR-2B, they will not get their tax refund, and they will likely stop buying from you.

Ramesh ran a successful D2C coffee brand. A corporate office ordered ₹1 lakh worth of coffee beans for their pantry and provided their GSTIN. Ramesh's Shopify store generated a standard B2C receipt without the buyer's GSTIN. Ramesh filed it as a B2C sale. A month later, the corporate client called, furious that they lost ₹5,000 in ITC. Ramesh had to amend his GST returns to fix a problem that a simple invoice setting would have prevented.

The Interstate vs Intrastate Rule

Your invoice must correctly apply the type of GST based on the shipping destination. This is called the "Place of Supply" rule.

If your registered warehouse is in Karnataka and you ship to a buyer in Karnataka, it is an intrastate sale. Your invoice must split the tax equally into CGST (Central GST) and SGST (State GST).

If your registered warehouse is in Karnataka and you ship to a buyer in Maharashtra, it is an interstate sale. Your invoice must charge IGST (Integrated GST) for the full tax amount.

E-commerce sellers face this daily. When you use Amazon FBA or Flipkart Smart Fulfilment, you might register an Additional Place of Business (APOB) in a different state. If your APOB is in Haryana and the product ships from that Haryana warehouse to a Haryana buyer, you charge CGST/SGST — even if your main office is in Delhi.

Tax is charged based on where the product begins its journey, not where your accountant sits.

E-invoicing Rules for E-commerce in 2026

E-invoicing does not mean sending a PDF in an email. In the Indian tax system, e-invoicing means electronically registering your B2B invoices directly with the government portal (IRP) before you send them to the buyer.

As of 2026, e-invoicing is mandatory for any business whose aggregate annual turnover exceeded ₹5 crore in any financial year since 2017-18.

If you cross this threshold:

1. Every B2B invoice you generate must be pushed to the Invoice Registration Portal (IRP).
2. The IRP generates a unique 64-character Invoice Reference Number (IRN) and a QR code.
3. Your final invoice to the buyer must contain this QR code.

If you sell B2B and fall under this mandate, an invoice without a valid IRN and QR code is legally invalid. The buyer cannot claim ITC, and the goods can be seized in transit.

For B2C sales, e-invoicing is not yet mandatory, but if your turnover crosses ₹500 crore, you must print a dynamic QR code on B2C invoices to enable UPI payments. Most e-commerce sellers do not need to worry about the B2C QR code rule yet.

Signatures: Digital, Physical, or None?

Do you need to print and physically sign every single invoice that goes into a courier bag?

No. The law allows for digital signatures.

If you sell on Amazon or Flipkart, the invoice generated by the marketplace's system includes a digital signature block. It usually reads: "This is a computer-generated invoice and does not require a physical signature." This is entirely legally valid under the Information Technology Act.

If you run a D2C brand, modern billing software like ClearTax or Zoho Books will automatically apply a digital signature to your PDFs.

What Happens If You Get It Wrong?

The GST department is strict about documentation because invoices are the foundation of the entire tax credit system.

Issue an incorrect invoice, issue an invoice without actually supplying the goods (fake invoicing), or ship goods without an invoice, and the penalty is severe. Section 122 of the CGST Act imposes a penalty of ₹10,000 or 100% of the tax evaded — whichever is higher.

Worse, if your shipment is intercepted in transit by a GST officer and the package does not contain a compliant tax invoice (and an e-way bill, if the value exceeds ₹50,000), the officer can seize the goods and the vehicle. The penalty to release them can be up to 200% of the tax amount.

When a Sale Changes After the Invoice: Credit Notes and Debit Notes

A tax invoice is not always the final word. If a buyer returns the goods, or if the price is revised after the invoice is issued, you cannot simply cancel and re-issue. GST requires a specific document.

Credit note: Issue a credit note when goods are returned, the buyer is given a discount after invoicing, or the price is reduced. The credit note reverses the GST charged and reduces your output tax liability. It must be issued by September 30 of the following financial year to be valid for that period.

Debit note: Issue a debit note when you need to charge the buyer more than what the original invoice showed — for example, if the actual weight of goods exceeded the estimate.

Both documents reference the original invoice number and must be reported in GSTR-1, just like regular invoices. If you issue credit notes and do not report them, your GSTR-1 will not reconcile with the buyer's purchase records.

Your Next Steps

If you are selling purely on marketplaces, download a sample invoice from your seller portal today. Look at the 16 fields. Understand how the marketplace is classifying your sales.

If you are running your own D2C site:

1. Stop using standard platform receipts. Shopify and WooCommerce basic receipts are not GST-compliant out of the box.
2. Install a GST invoicing app. Use an India-specific plugin or integrate your store with Zoho Books or ClearTax.
3. Enable B2B fields at checkout. Add an optional "Company Name" and "GSTIN" field to your checkout page so business buyers can request proper B2B invoices.

Once your invoices are compliant, your next job is making sure they are reported correctly to the government each month through GSTR-1. Read our step-by-step GSTR-1 filing guide for the full portal walkthrough. If your sales volume is growing and filing is becoming a headache, our assisted GST return filing service handles the monthly compliance for you.