There are two different concepts of QR Codes when it comes to e-Invoicing in India.
In order to issue an e-Invoice, a taxpayer has to prepare a valid invoice in electronic format as per the e-Invoice schema and submit it to a government authorized Invoice Registration Portal (IRP).
The IRP will validate the invoice and also generate a QR code containing the unique Invoice Reference Number along with some important parameters of invoice and digital signature so that any person such as the recipient or tax officer could verify the details of the invoice. The QR Code contains important details of the invoice so that one can check those details even without internet access. The QR code will consist of the following e-invoice parameters:
It is expected that suppliers include the QR Code while generating PDF format of the invoice or printing the invoice on paper. However, there is no legal requirement at present to display the QR code on the invoice.