The document discusses the key aspects of e-invoicing under GST in India. It notes that as per the latest notification, e-invoicing will be mandatory for registered persons whose aggregate turnover in the previous financial year exceeds Rs. 500 crores and will come into effect from October 1st, 2020. It will not apply to SEZ units or sectors like insurance, banking, financial institutions, goods transport, and passenger transport. The invoice registration portal will generate a unique invoice reference number after the specified persons upload the invoice details. E-invoices can only be cancelled on the IRP within 24 hours, while amendments and cancellations can continue to be done on the GST portal as per existing provisions.