Doudian Merchant Invoicing means that when a merchant sells goods or provides services, in order to prove the authenticity of the transaction, the merchant issues a legal and valid invoice to the buyer. Doudian Invoicing means that the merchant issues an invoice to the buyer through the Doudian platform to prove the transaction of the goods sold or services provided by the merchant to the buyer. Doudian invoice is a tax invoice, which is issued by the local invoice center. The buyer can go to the local tax authority to handle the invoice issuance, verification and related tax reporting procedures based on the invoice information provided by the Doudian platform.