In the GST system, e-invoicing is a process that allows businesses to electronically authenticate B2B invoices through the Goods and Services Tax Network (GSTN). The invoices are then uploaded to the Invoice Registration Portal (IRP) and the IRP generates a unique Invoice Reference Number (IRN) for each invoice. The IRP also digitally signs the e-invoice and returns it to the user along with a QR code.
The E invoice copy contains the Acknowledgement number, IRN number and QR code.