The invoice should be stamped. Invoices that are not stamped have no legal effect, and can only be used as the original basis for business vouchers and bookkeeping after being stamped. According to the relevant laws and regulations of our country, invoices should be issued at one time and stamped with special invoices in accordance with the prescribed time limit, order and columns.

The functions of invoices are as follows:

1, invoice has the characteristics of legality, truthfulness, uniformity and timeliness, and is one of the most basic accounting original vouchers;

2. Invoice is the carrier of recording economic activities and an important tool of financial management;

3 invoices are an important basis for tax authorities to control tax sources and collect taxes;

4. Invoice is an important means for the state to supervise economic activities, maintain economic order and protect national property safety.

Legal basis: Article 19 of the Measures for the Administration of Invoices in People's Republic of China (PRC).

When applying for receiving and purchasing invoices from units and individuals in other provinces, autonomous regions and municipalities directly under the Central Government engaged in temporary business activities, the tax authorities may, according to the face value and quantity of the invoices received, require them to provide a guarantor or pay a deposit of not more than 10,000 yuan, and hand in the invoices within a time limit.

If the invoice is paid off on schedule, the guarantor's guarantee obligation shall be released or the deposit shall be returned; If the cancellation invoice is not paid on time, the guarantor or deposit shall bear legal responsibility.

The tax authorities shall issue a receipt when collecting the deposit.