1. Invoices refer to business vouchers issued and collected by all units and individuals in the course of buying and selling commodities, providing or receiving services and engaging in other business activities;

Two, the invoice is the original basis of accounting, but also an important basis for law enforcement inspection of audit institutions and tax authorities. The receipt is the proof of payment, and the invoice can only prove that the business has happened, but can't prove whether the money has been paid or not;

Third, the significance and role:

1. Invoice has the characteristics of legality, authenticity, unity 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. Invoice is an important basis for tax authorities to control tax sources and collect taxes;

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