E-Invoicing System – Format and Mandatory Fields

An overview of the e-invoice format

As per directions by GST Authority, a time limit of 30 days for reporting of invoices from date of invoice is imposed on e-invoice portals, and is applicable for taxpayers with AATO greater than or equal to 100 crores from 1st November 2023.

In this post, we will explore the e-invoicing format and the mandatory fields included in e-invoicing under GST. Let’s take a brief look at these sections.

Latest Update: Starting August 1, 2023, e-invoicing will be applicable for businesses with an annual turnover of 5 crore and above.

What is e-invoicing under GST?

The e-invoice, also known as the ‘electronic invoice’, is a system of uploading and authenticating all B2B invoices electronically. IRP generates an Invoice Reference Number (IRN) for each invoice following successful authentication. 

Each invoice is digitally signed and assigned a unique Invoice Reference Number (IRN) and a QR code. This process is collectively known as e-invoicing under GST.

Format of sample e-invoice

The e-invoice format is a standard template businesses use to report invoice details electronically. The format is detailed in Form GST INV-1, a government document. Companies must report their invoice details in JSON format to the Invoice Registration Portal (IRP).

The e-invoice format has eight main parts, each with specific details that need to be mentioned. Here are the eight main parts of the e-invoice format:

  • Invoice item details
  • Receipt/contract references
  • Preceding document/contract reference
  • Basic details
  • Ship-To details
  • Delivery information
  • Payee information
  • Supplier information
  • Dispatch from details
  • Document total
  • Extra information like port code, batch details, etc.

As per the e-invoice format, specific details must be mentioned while sending the invoice details to IRP. Depending on the nature of business and transactions, some details can also be optional.

What are the mandatory fields of an e-invoice?

The e-invoice format is based on the GST invoicing rules and is designed to accommodate each industry or sector’s invoicing system and policies. 

It has mandatory and optional information, so businesses can only fill in the relevant fields. The e-invoice contains certain fields from the e-way bill format.

The list of compulsory fields under e-invoicing under GST:






Invoice Reference



(Max length:64)



Unique reference number of the invoice. The supplier can not populate this field. The IRP will generate this IRN and respond to the registration with the IRN.

Invoice is only valid once it has the IRN.


Code for Supply type

(Max length:10)



A code to identify the type of supply.


Code for the Document type 

Invoice /  Credit Note / Debit Note

Type of the document can be used as Invoice, Credit or Debit note.


Document number 

(Max length:16)


It will be as per invoice number rule mentioned in CGST/SGST/UTGST Rules.


Document Date 


The issue date of the e-invoice.


Supplier Information 

Legal Name, GSTIN, address, Place/City/Town, State, PIN Code

Information about the supplier.


Buyer Information 

Legal Name, GSTIN, address, Place/City/Town, State, PIN Code

Information about the buyer.


Invoice Item Details

Serial Number, Service, HSN code, Item Rate per unit quantity, Gross amount,  Net amount, GST Rate, Item total amount

Provides information about the goods and services invoiced.


Total Amount in INR 

Decimal (13,2)


The total amount of the invoice including GST must be rounded off to two decimals.



(Max length:10)

Only for GST supplies.


E-way Bill Details 

Transporter, Mode of transportation, Distance of transportation.

these details to be provided.


Shipping to

Legal Name, Address, Place, PIN code, State Code

Of the entity to which the supplies are shipped to.


Dispatch From Details

Name, Address, Place, PIN code, State Code

Of the entity from which goods are dispatched.


The total taxable value of the invoice

Decimal (13,2)


The sum of the taxable amounts of all the items in the document.


Batch number/ name 

(Max length: 20) 673927

Batch number details may be relevant for a certain set of manufacturers.



This concludes the post on e-invoicing format and the mandatory fields included in e-invoicing under GST. Please share your views and opinions with us in the comment section below.

FAQs on e-invoicing

1.Why is e-invoice required ?

Ans: E-invoicing is essential for many reasons, including the reduction of mistakes, the saving of time, the improvement of compliance, and the prevention of fraud.

2.What is the difference between e-invoice and an invoice ?

Ans: Invoices are documents that sellers give to buyers to list the goods or services they provided, along with the quantity, price, taxes, and discounts. E-invoices are digital versions of invoices that are generated and validated by a government portal.

3.What are the types of documents that need to be reported to the IRP?

Ans: Invoices, credit notes, and debit notes issued by suppliers, as well as any other document as notified under the GST law, must be reported as e-invoices to the IRP.