0.3. Electronic signature: what it is and what it's for.

An electronic signature certificate in Spain is a digital document issued by a recognized certification authority that uniquely identifies a person or entity and allows documents to be signed electronically with legal validity, equivalent to a handwritten signature on paper. 

What exactly is it?

• It is a digital file containing your identification data (name, NIF/NIE, cryptographic keys, etc.). 
• It allows you to sign documents electronically and access or carry out online procedures with public administrations, banks, companies, or other organizations securely and with legal validityIt guarantees the
• signer's identity, the document's integrity and that the signature truly originates from the certificate holder. 

What is it used for?

With an electronic signature certificate, you can:

• Submit taxes, appeals, or declarations to the administration. 
• Access services such as Social Security, Tax Agency, city councils, or official registries. 
• Sign contracts and digital documents with legal validity. 

How is it obtained in Spain?

The most common method is to obtain the electronic certificate from the FNMT-RCM (National Mint and Stamp Factory – Royal Mint), which is free, although there may be a small cost if you choose video identification. 

Main steps

1. Request the certificate online
   Access the FNMT website and fill out a form with your personal data (NIF/NIE, name, etc.). After submitting the request, you will receive an application code in your email. 
2. Verify your identity
   With that code, you must verify your identity at a physical registration office (for example, points of the Tax Agency, Social Security, or other collaborating organizations). It is also possible to verify your identity online with video identification or using your electronic DNI (DNIe) or an existing certificate. 
3. Download and install the certificate
   Once your identity has been verified, you can download the certificate from the FNMT website using the same computer and browser with which you made the request. 
4. Save backup copy (optional but recommended)
   After installing it, save a backup copy on a secure device to be able to reuse or restore it if you change equipment. 

Basic requirements

• Have a valid DNI or NIEBe of legal age (or emancipated minor). 
• Have an email address and, in some cases, means to verify your identity (DNIe or video identification).