1. Definition: The "three-in-one" principle of external invoicing is stipulated from the perspective of the invoicing VAT party. The so-called "trinity" means that the capital flow (receipt and payment voucher of the bank), ticket flow (invoice drawer and invoice payee) and logistics (or labor flow) are unified with each other, that is, the payee, drawer, goods seller or labor provider must be the same legal entity.

2. The specific contents include:

(1) Taxpayers sell goods or provide VAT taxable services to paying taxpayers;

(2) The taxpayer has charged the taxpayer of the payer the price for selling goods, providing taxable services or providing taxable services, or obtained the evidence for asking for the price;

(3) The contents of the special VAT invoice issued by the taxpayer to the paying taxpayer in accordance with the provisions are consistent with the sale of goods, provision of taxable services or taxable services, and the special VAT invoice is legally obtained by the taxpayer and issued in its own name.