1. Electronic signature software: Using professional electronic signature software and adding electronic signature to electronic invoices can realize the authentication and authorization of electronic invoices;

2. Electronic signature service platform: register an account on the electronic signature service platform, and use the electronic signature tools provided by the platform to sign and authenticate electronic invoices;

3. Electronic authentication institutions: You can apply for electronic signature service from qualified electronic authentication institutions, and add electronic signature to electronic invoices to realize the authentication and authorization of electronic invoices.

The materials required for stamping electronic invoices are as follows:

1. Account number of billing system: you need to apply for an account number in the billing system and provide relevant identification information;

2. Basic information of the enterprise: Basic information of the enterprise, including the name of the enterprise, taxpayer identification number, etc., shall be provided;

3. Invoice application materials: invoice application materials are required, including invoice header, invoice type, invoice date, etc.

4. electronic seal file: electronic seal file, including seal certificate and seal password, should be provided.

It should be noted that although adding a seal to an electronic invoice can achieve a certain effect, it has no legal effect and is easy to be forged. If you need to use a formal invoice, please choose a formal way and abide by the tax laws.

to sum up, the signature and authentication of electronic invoices are important links to ensure their legitimacy and effectiveness, and relevant laws, regulations and policy requirements must be strictly observed.

Legal basis:

Article 19 of the Measures for the Administration of Invoices of the People's Republic of China

Units and individuals that sell goods, provide services and engage in other business activities collect money from foreign businesses, and the payee shall issue invoices to the payer; Under special circumstances, the payer will issue an invoice to the payee.