Latam Living logo in SVG format.

Efirma with SAT and its Benefits

SAT’s “efirma” Signature TL;DR

The efirma del SAT is an official electronic signature in Mexico. It’s used to carry out legal and tax procedures in a secure, digital fashion and with full legal validity. Individuals and businesses (legal entities) can make an appointment to apply for an efirma at a SAT office. It’s valid for 4 years and can be renewed online.

Section separator for Latam Living.

What is the SAT efirma?

The SAT’s efirma, also known as FIEL (Firma Electrónica Avanzada), is a set of digital files that allow you to validate your identity when carrying out procedures online. This tool, issued by the Tax Administration Service (SAT), has full legal validity in Mexico. Its purpose is to facilitate fiscal and legal processes without forcing people to have to go to an office in person. You can use it with other institutions such as IMSS, Infonavit, and even private companies.

My efirma Appointment with SAT

I processed my SAT efirma without complications. At the appointment, they reviewed my documents, took my biometric data and at the end they gave me my USB with all the necessary files. It was easier than I expected.

efirma in Mexico

Functions of the efirma

The SAT efirma allows you to perform online procedures in a secure and encrypted way. Some of its most important functions are:

  • File tax returns with the SAT
  • Sign digital documents with legal validity
  • Perform procedures in other government agencies such as IMSS or Infonavit
  • Issue digital invoices
  • Sign contracts digitally
Section separator for Latam Living.

How to Get an efirma from SAT

First I’ll clarify Mexico’s meaning behind “persona moral” and “persona física” as the “moral” part can be a bit confusing. It has nothing to do with someone’s ethics or whether they’re a good person or not. In Mexico, the term “persona moral” refers to a legal entity such as a company or organization. The word moral here comes from the Latin moralis, meaning “social” or “collective,” and is used in the same way in France (personne morale). All other Latin American countries, including Brazil (Portuguese), and Spain in Europe use the term “persona jurídica”, which carries the same meaning: a “legal person” recognized by law, as opposed to a natural person.

  • Persona física = individual
  • Persona moral = company

Requirements for efirma Persona Física

  • Email address
  • Get an appointment from the SAT appointment portal
  • Bring a USB memory stick to appointment
  • Valid identification
  • Proof of address (if your ID doesn’t have address)—most people use electric bill

Requirements for efirma Persona Moral

  • Email address
  • Get an appointment from the SAT appointment portal
  • Bring a USB memory stick to appointment
  • Valid identification
  • General power of attorney to act as administrator and/or owner
  • Proof of tax domicile
  • The legal representative must have an e. firma as a persona fisica
Section separator for Latam Living.

What to Expect at efirma SAT Appointment

During the appointment, a SAT representative will verify the documentation you provided and digitalize (scan) them. Additionally, another representative will register your biometric data consisting of 10 fingerprints, facial photograph, a photo of the iris in both eyes and your signature.

Dark blue digital screen showing a person's hand and five spread fingers with fingerprints somewhat similar to efirma fingerprints taken in Mexico.
Fingerprints for efirma at the SAT office is done digitally.

How the SAT efirma is Created

Certain computer files are needed to digitally sign documents on the SAT portals or other government platforms. When you complete your efirma appointment, you will have the following files on your USB memory stick:

  • A digital certificate (.cer file)
  • A private key (.key file)
  • A password that protects your private key

Validity of the SAT efirma

Your SAT efirma is valid for four years. You can renew it online before it expires without having to go to the SAT office again.