What is an “electronic signature” (“firma electrónica”/ “certificado electrónico”/ “certificado digital”) and what is it good for?

In my experience, many people in Spain unfortunately do not know what a so-called “electronic signature” (called “firma electrónica”, “certificado electrónico” or “certificado digital” in Spanish) is and how extremely useful it can be. To change that, here’s my article about the topic.

An article published on: 24th October 2020 


Spain is quite advanced when it comes to the use of electronic methods. This means that it is possible to get almost any kind of official business done online, without having to go to the different public agencies.

For example, you can apply for unemployment benefits, check how much you have accumulated in pension rights, check which postal address is registered with the tax authorities and see the processing status of all kinds of applications or claims you have submitted.


Of course, some people prefer doing everything in person, which does have its advantages, since it is certainly easier to understand an issue when discussing it with the relevant civil servant and it is also possible to explain more easily what you actually want (but then one needs to speak Spanish and must not be deterred by the occasionally somewhat unfriendly civil servants).


However, in many cases the Spanish authorities “force” citizens to manage their affairs online (for example, the self-employed must communicate with the tax and social security authorities by electronic means, and they are not allowed to submit anything in person). This is also true if you go to the social security office to request a certificate showing the periods in which you have worked, for example. These certificates are not issued by civil servants, but rather, there are computers available where you are supposed to print out this certificate yourself. 

1.) How is official business done online?

In order to be able to take care of matters with the Spanish authorities directly online, it is necessary to identify oneself online, i.e., a clear means of identification is required.


This is possible in Spain with:

  • an electronic National ID card (DNI electrónico)
  • an authentication method using a password and PIN number, the so-called “Cl@ve PIN” or “Cl@ve permanente” and
  • an electronic signature, known as “firma electrónica” or “certificado electrónico/digital”

Without one of these unambiguous types of identification, personal data cannot be accessed or conveyed.

2.) How does a “firma electrónica” differ from a Cl@ve PIN, etc.?

  • The electronic National ID card (“DNI electrónico”) is linked to the Spanish ID, which means it is only available to Spaniards.
  • Cl@ve PIN and Cl@ve Permanente are authentication methods that work in a manner similar to online banking. First, you enter a password, then type in a PIN and after that you receive an SMS. So you always need a mobile phone. To register for this authentication method, you must visit the tax or social security offices once in person.
  • The electronic signature (“firma electrónica” or “certificado electrónico”) is a certificate that is installed in the internet browser on your computer. When a website is opened in which identification is required, a pop-up window automatically appears, you click on your electronic signature, confirm, and then it is as if you had signed in person. This means that no PIN must be sent by SMS, so no mobile is needed (although a PC is required instead), and precautions must be taken to ensure that no one can use your electronic signature without authorisation. To be able to use this authentication option, you must also visit the tax or social security offices once in person.

3.) Which is better: “Certificado digital”, or Cl@ve PIN, etc.?

I prefer the electronic signature (certificado digital/ electrónico), although this is my personal opinion.

It can be used at almost any public agency. The only disadvantage is that it cannot be used on a mobile phone. However, I think most people would prepare their tax statements or other official forms on a computer rather than a mobile anyway, since the screen is bigger.

Moreover, foreigners only living for a certain time in Spain, in particular, will eventually no longer have their Spanish mobile number. Even just changing mobile phone numbers in Spain creates problems with the Cl@ve PIN.

4.) Who should get an electronic signature?

I would advise every foreigner in Spain to create an electronic signature. Spaniards always have the option of using their normal ID card as online identification (DNI electrónico) anyway, so I would especially recommend it to non-Spaniards.


I would also suggest that any foreigners who do not live in Spain but own property here, for example, also get an electronic signature as an online identification method.

5.) Why is online identification important? What is the purpose?

a) Anyone living in Spain can spare themselves a lot of time and trouble by doing official business online.

Government offices in Spain are usually open Mon.-Fri. from 9:00 am to 2:00 pm and an appointment is almost always necessary.

But who has time between 9:00 am and 2:00 pm? And anyone who has attempted to make an appointment under the current circumstances, with the restrictions related to the COVID crisis, knows that this can be a truly hopeless endeavour...

It is much better to be able to get everything conveniently done on a computer in a timely manner, since there is no need to wait for the next available appointment.


What kinds of procedures can be done online? 

  • Submitting tax statements
  • Filing applications and claims (with the tax or social security authorities, or with the employment office, for example)
  • Registering or de-registering with the municipal authorities (registry office)
  • Checking or changing details at the land registry
  • Signing up for municipal sport or continuing education courses, etc.

b) A power of attorney can be granted without difficulty so that someone else can take care of official affairs.

Even if you cannot or prefer not to take care of your affairs with the tax or social security authorities or the employment office, and so on, yourself, electronic identification offers the perfect opportunity to issue a power of attorney online and to appoint a representative (otherwise you have to visit each respective office yourself).

c) Anyone who does not live in Spain but has to deal with the public authorities in Spain (such as owning a holiday home in Spain) should get an electronic means of authentication as quickly as possible.

This greatly facilitates access to notifications from the tax agency, municipal authorities (real estate tax, waste collection, etc.), the registry of deeds or cadastre office. And it is perfectly suited to having a representative take care of everything, without having to travel to Spain personally or to involve a notary.

d) I would like to devote one remark specifically to foreigners who want to (or need to) submit their income tax return in Spain for the first time.

A typical problem arises when foreigners want to or need to prepare their income tax statement in Spain for the first time.

Regardless of whether you wish to access your data and prepare and submit your statement yourself, or if you hire a tax consultant to do so, you are required to have a so-called “reference number” (“número de referencia” in Spanish).

In order to obtain this number, certain personal data must be entered. But that may not necessarily be enough to generate a reference number. In that case, the only way to get a reference number is to go to the tax office oneself. During submission periods, however, it is usually difficult to make an appointment on short notice (or at all).


On the other hand, if an electronic means of identification is already available, the reference number can be generated easily, thus making it possible to prepare the tax return. 

6.) How does one get an electronic signature (“certificado electrónico”)?

Now that I have hopefully made it clear how truly practical and extremely useful it is to have an electronic signature, the next question is, how to apply for one.


As is almost always the case, you can do this yourself, or you can have an authorised representative take care of it for you.

a) Applying for a “certificado digital” oneself:

Anyone who can speak Spanish and has the time can apply for their own electronic signature. Further information can be found here. Those who live abroad can process the application at a Spanish consulate office.


I have written a step-by-step manual on how to obtain your digital signature in Spain (by yourself), you can find more information about it here.

PDF-Instructions: "7 steps to obtain your digital signature" - This is a guide that shows you how to apply for your online-ID to easily identify yourself online before public authorities in Spain.
NEW: My eBook on how to obtain your electronic signature in Spain - It is that easy.

b) Having a representative apply for an electronic signature:

Those whose Spanish is not (yet) very good, or who live abroad, can have a representative apply for their electronic signature. You are welcome to contact me to do so!

Conclusion: having an electronic signature (certificado electrónico) is worth a mint!

My intention with this article was to show how advantageous it is to have an electronic signature.


Having electronic means of identification available is especially practical for foreigners in Spain and individuals who live abroad but have interests in Spain (such as real estate). 


It enables them to generate their reference number for income tax statements, to submit tax statements of all kinds and to notify changes in their circumstances directly online. Numerous public authorities, whether it is the Spanish social security office, tax agency, employment office or cadastre, as well as all the municipal authorities (empadronamiento, municipal continuing education or sport courses, etc.), offer the chance for individuals to identify themselves online and handle their official affairs online. 


If all of this sounds great, but you would rather not deal with it yourself, then contact me and I can help you apply for your electronic signature!


Do you still have questions regarding this matter? Then write to me and make a consultation appointment!

I’d be delighted to help you through each step of the way. It is that easy.