Complete guide to installing AutoFirma and filing your tax return easily

If you are going to file your income tax return online this year, you have probably already heard about AutoSignatureThis tool has become essential for carrying out numerous administrative procedures from home completely digitally, including one of the most common and anticipated procedures of the year: the income tax return.

AutoFirma is an application developed by the Spanish Government that allows you to electronically sign documents from your computer or mobile phone, a fundamental feature when validating documents on official platforms such as the Tax Agency. In this guide, we explain in detail. What is AutoFirma, how to install it on PCs and mobile phones, how to configure it, and how to use it to complete procedures such as filing your tax return.We also include practical tips, troubleshooting, and other helpful features.

What is AutoFirma and what is it for?

AutoSignature It is a desktop and mobile application developed by the Ministry of Economic Affairs and Digital Transformation that allows digitally sign documents and carry out online procedures within public administration platforms. Its use ranges from signing local files (such as PDF or XML) to integration with web procedures on portals such as the Tax Agency, the SEPE (Spanish Public Service), the Ministry of Industry, among many others.

The software uses digital certificates to validate your identity and ensure the authenticity of the signed document. These certificates can be hosted on the operating system keystore, in it web browser or even in external devices such as the DNIe or smart cards. In addition, AutoFirma supports different electronic signature formats: XADES, PADES and CADES, which adapt to different types of documents and legal requirements depending on the procedure.

Prerequisites for using AutoFirma

• Valid digital certificate: must be in force, not expired or revoked.
• Compatible operating system: Windows (7, 8, 8.1, 10, 11), macOS (Ventura, Monterey, Big Sur), Linux (Ubuntu, Fedora, OpenSUSE).
• Administrator privileges: are required to install or configure AutoFirma.
• Temporarily disable antivirus or firewall (in some cases), to avoid blockages during installation.

How to download and install AutoFirma on computers

To do this correctly, it's best to access official sources. You can download AutoFirma from:

• The Electronic Administration Portal: firmaelectronica.gob.es
• The Tax Agency website: usually offers redirection to the official download portal.
• The electronic headquarters of ministries such as Industry and Tourism, or Digital Transformation.

Once you have downloaded the file corresponding to your operating system, you just have to run the installer and follow the wizard's steps. It's recommended to close all browsers before starting the installation and restart them afterward so that AutoFirma can integrate properly.

Browser compatibility

AutoFirma works with popular browsers such as Microsoft Edge, Google Chrome, and Mozilla Firefox. However, there are a few settings to keep in mind:

• Firefox: uses its own certificate store, so it is recommended to enable the “trust the operating system store” option.
• Chrome and Edge: They use the system store directly, so they do not require additional steps if the certificate is properly installed.

If you installed AutoFirma before the browser, you may need to restore the installation for it to configure correctly.

Installing AutoFirma on mobile devices

AutoFirma on Android

On Android devices, you can install AutoFirma by following these steps:

1. Go to the Google Play Store and search for “AutoFirma” or “@firma Mobile Client.”
2. Select the official Ministry app and click “Install.”
3. When you open the app, grant permissions to access files and documents.
4. Import your digital certificate using the “Import certificate” option.
5. You can now sign documents using the “Sign File” button.

AutoSignature on iOS (iPhone and iPad)

If you have an Apple device, the process is similar:

1. From the App Store, search for “AutoFirma” or “@firma Mobile Client.”
2. Download the official app and open it.
3. Go to “Manage Certificates” and click the “+” symbol to add a new one.
4. Select your digital certificate file and insert it.

How to obtain and import your digital certificate

Before using AutoFirma you will need a valid digital certificateIf you don't have it yet, you can request it through the National Mint and Stamp Factory or use the DNIe with NFC. Once you have it:

• Make a copy of the certificate from the web browser.
• Include the private key when exporting (check the box).
• Protect the file with a password to use with AutoFirma.

Remember to give it a short, memorable name so you can easily locate it in the app. If you use NFC, make sure your chip is active and your e-DNI PIN is updated.

How to sign documents with AutoFirma

Once AutoFirma is installed and your certificate is uploaded, signing documents is very simple:

• Open AutoFirma and click on “Select files to sign” or drag them to the gray area.
• Select the file to sign (PDF, XML, DOC…).
• Choose the digital certificate and confirms.
• Save the document signed wherever you prefer.

In ministerial settings, such as the Treasury, Recommended signature format is XADESYou can set it by default from the menu: “Tools ➔ Preferences ➔ Formats”.

Use AutoFirma to file your income tax return

When you enter the Tax Agency portal and access the "Income Tax 2024" section, the system will ask you to log in. You can do so with:

• Digital certificate
• Electronic ID card
• Cl@ve PIN or Permanent Cl@ve

Once you have entered the data for your declaration, before submitting it, the signing process with AutoFirma will be activated. You just need to follow the steps guided by the system. After submitting the form, you will receive a legally valid proof.

Combine AutoFirma with Cl@ve Mobile

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Cl@ve Móvil (formerly Cl@ve PIN) is another official tool that allows you to identify yourself using a PIN sent to your mobile phone. You can Use Cl@ve to access the system and AutoFirma to sign documents, streamlining the process. This combination is ideal for users who don't want to rely solely on the operating system's digital certificate.

Common errors and problems

The certificate is not displayed

This could be due to an expired certificate or one that isn't uploaded to the system store. Make sure it's properly installed and up-to-date. If you need more information on how to sign a PDF, you can consult this article. link.

Permissions on mobile devices

Grant access from your phone's settings if AutoFirma can't access your storage.

Errors with DNIe

Make sure you have version 3.0 of your eDNI and NFC enabled. Enter the PIN when prompted and hold your phone over your DNI while the card is being read.

Problems on macOS

The system may block installation if it's from outside the App Store. Use "Control-click the app ➔ Open" to force installation.

AutoFirma Update

From “Tools ➔ Preferences,” enable the “Check for updates at startup” option to ensure you always have the latest version.

Extra tips to improve your experience

• Temporarily disable antivirus if it blocks the installation.
• Don't change browsers after installing AutoFirma, or restore the installation.
• Save a backup copy of your certificate in a safe place, in case you need to reinstall.
• Check the validity of the certificate on the VALIDe platform (redsara.es).

AutoFirma may seem complex at first, but once configured correctly, it becomes a very powerful and useful tool. Install it, Both on computers and mobile phones, it will allow you to submit your Income Tax and other procedures in a comfortable, safe and legal way.. In addition, its combination with other identification platforms like Cl@ve Mobile gives you complete flexibility to operate the administration from wherever you want. If you follow the procedures step by step and keep your certificate up to date, Signing documents will be as easy as a click.

Related article:

How to sign a PDF with an electronic signature without installing programs

Alberto Navarro

I am a technology enthusiast who has turned his "geek" interests into a profession. I have spent more than 10 years of my life using cutting-edge technology and tinkering with all kinds of programs out of pure curiosity. Now I have specialized in computer technology and video games. This is because for more than 5 years I have been writing for various websites on technology and video games, creating articles that seek to give you the information you need in a language that is understandable to everyone.

If you have any questions, my knowledge ranges from everything related to the Windows operating system as well as Android for mobile phones. And my commitment is to you, I am always willing to spend a few minutes and help you resolve any questions you may have in this internet world.