the time before the invoice is opened cannot be added. The time shown on the invoice is the time of invoicing, which is automatically generated by the invoicing software and cannot be changed by itself. However, the contents of the invoice issued can be the contents of the previous purchase and sale, that is to say, the invoice was not issued at that time when the purchase and sale occurred, and the invoice was issued later. This is ok, but the time on the invoice is the current invoicing time.