There is no time limit. The Measures for the Administration of Invoices in People's Republic of China (PRC) stipulates that units and individuals that sell goods, provide services and engage in other business activities shall collect money from outside, and the payee shall issue invoices to the payer. All units and individuals engaged in production and business activities shall also ask the payee for invoices when purchasing goods, receiving services and engaging in other business activities. In other words, enterprises should take the initiative to issue invoices to payers after conducting business and collecting money. Even if the invoice was not issued at that time, consumers can make up the invoice at any time afterwards. Even the last year's transactions can be invoiced. It is illegal for an enterprise to set the validity period of invoicing privately and refuse to invoice.