Units and individuals using invoices shall properly keep invoices. In case of loss of invoices, a written report shall be made to the tax authority on the day when the loss is found, and a statement shall be published in the newspaper to invalidate the invoice.
 1、 Invoices refer to the business vouchers issued and collected by all units and individuals in the purchase and sale of goods, provision or receipt of services, and other business activities. They are the original basis for accounting and an important basis for the audit and tax authorities to carry out law enforcement inspections. The receipt is the receipt and payment voucher. The invoice can only prove that the business has occurred, not whether the payment is received or not.
 2、 Any unit or individual shall use invoices in accordance with regulations on invoice management and shall not commit any of the following acts:
 （1） Lend, transfer or introduce others to transfer invoices, invoice supervision seal and special products for anti forged invoices;
 （2） Know or should know that invoices are privately printed, forged, altered, illegally obtained or invalidated, and are transferred, drawn up, stored, carried, mailed or transported;
 （3） Use invoices in separate copies;
 （4） Expand the scope of invoice use;
 （5） Use other vouchers instead of invoices.
 [Legal Basis]
 Article 31 of the Detailed Rules for the Implementation of the Measures of the People's Republic of China for the Management of Invoices states that units and individuals using invoices shall properly keep invoices. In case of loss of invoices, a written report shall be made to the tax authority on the day when the loss is found.