Hello dear 1. Open the invoicing software, in "System Parameter Settings - Parameter Settings - Running Parameters", set "Use Custom Classification Coding Mode" to use "Commodity Classification Coding Usage Mode". 2. Open the original product code: System Settings - Product Code - Value-Added Tax Product Code (for motor vehicles or cargo transportation, select the motor vehicle product code and cargo transportation product code respectively) 3. Add a large category first: click on the product Information Category - "+" - Enter the category name such as 04, add the product and then assign the code: click the Add button---enter the product name, such as catering expenses---click the assign code (or you can directly click on the original product code, and then Click to assign the code 5. You can find the corresponding category through keywords---click to select---select the tax rate---check whether tax is included---click OK 6. After prompting that the operation is successful, click OK; when invoicing You can use it 7. Invoice issuance: Invoice management---Invoice filling---Select the invoice type to fill in (such as general invoice) 8. After entering the buyer's information, select the product for issuance, you can choose " "Select the product. 9. Select the product we coded and double-click it. 10. After filling in other information, click print and the issue will be successful.