The electronic invoice is valid for one month, and it will be invalid after expiration. Electronic invoices are issued to merchants by state organs, with special anti-counterfeiting mechanism and signature of tax authorities, which can better protect the security of invoices and effectively crack down on illegal and fraudulent acts. Different merchants set different billing time. If users need to issue invoices when spending outside, they must understand the relevant matters with the relevant staff to avoid missing the time and being unable to issue invoices.