The coding principle of ordinary invoice code is basically the same as that of special invoice. The meaning of the 10 code in the upper left corner of the invoice: 1-4 digits represent the province. The 5th-6th place represents the plate-making year. Number 7 stands for print batch. The eighth digit represents the type of invoice, and the ordinary invoice is represented by "6". The 9th digit represents several versions, two versions of general invoice are indicated by "2", and five versions of general invoice are indicated by "5". The number 10 represents the amount, and the version number "0" represents the computer version.