The GST rules provide the e-invoice requirement under sub-rule (4), (5) and (6) of rule 48. It applies to individual taxpayers only. So, the rest of the taxpayers must follow standard invoicing provisions. The e-invoice system requires intimation of all the B2B supply transactions to the government by way of uploading invoices on the IRP (invoice registration portal). A taxpayer can first generate an invoice or the debit or credit note on his accounting software/ERP. Thereafter, he/she must upload the invoice on the IRP. On uploading the invoice, a unique Invoice Reference Number (IRN) will be issued against each invoice. Non-generation of e-invoices will imply non-intimation of supply transactions to the government. Any invoice issued by the applicable taxpayer without the IRN is considered an invalid invoice under the GST law. In other words, it is regarded as a non-issue of invoice and thus attracts various penalties as listed in the next section.