invoice issuing: according to the realized income, issue invoices with corresponding content, quantity, unit price and amount. The accounting treatment of invoicing is: debit: accounts receivable and other subjects, credit: main business income, payable taxes-payable value-added tax (output tax). Tax declaration: for ordinary taxpayers, the VAT shall be declared according to the output tax and input tax, the additional tax shall be declared according to the VAT payable, the income tax shall be declared according to the total profit, and the stamp duty shall be declared according to the signing of the corresponding contract.