Businesses exempt from e-invoicing

Notification 13/2020-CT as amended exempts certain classes, including insurers, banking companies, financial institutions and NBFCs, goods transport agencies, suppliers of passenger transport, multiplex admission to cinema, SEZ units, and government departments and local authorities.

If you are in an exempt class, you need not generate IRNs even above ₹5 crore. But buyers' systems often expect an IRN from large suppliers, so file the self-declaration of exemption on the e-invoice portal and mention it on invoices. Check the latest list, since classes have been added over time.