According to Article 22 of the Measures for the Administration of Invoices of the People's Republic of China, invoices shall be issued in a lump sum in accordance with the prescribed time limit, sequence and columns, and stamped with special invoices.

Special seal for invoices means that enterprises, units and individual industrial and commercial households must affix special seal for invoices when purchasing and issuing invoices. When the special seal for invoices is wrongly stamped, it must be voided, the invoice should be reopened, and then the correct seal should be stamped.