发票，是指在购销商品、提供或者接受服务以及从事其他经营活动中开具、收取的收付款凭证。具有法定效力，它既是保护消费者合法权益的重要证据，也是广大消费者向国家缴纳的税款进入国库的重要凭证。众所周知，税收是财政的主要来源，是财政收入的支柱，国家一方面向广大纳税 Invoices, refers to the purchase and sale of goods, providing or receiving services and engage in other business activities issued, received payment vouchers. It has the legal effect. It not only serves as an important proof to protect the legitimate rights and interests of consumers, but also serves as an important voucher for the vast amounts of tax paid by consumers to the state. As we all know, tax revenue is the main source of finance and a pillar of fiscal revenue. On the one hand, the state taxes large amounts of tax