Need. Electronic invoice is the product of the information age. Like ordinary invoices, they are distributed to merchants in the form of unified issuance by the tax bureau. The invoice number is distributed to merchants with national unified coding and unified anti-counterfeiting technology. The electronic invoice is accompanied by the signature mechanism of the electronic tax bureau. An electronic invoice must be issued to the tax bureau. Electronic invoice refers to the receipt and payment voucher in the form of data message issued or collected in business activities, that is, electronic invoice.