Multi-Factor Authentication (MFA) or Two-Factor Authentication (2FA) has been around a long time.  It is a process of using something you know (password) with something you have (token) to provide access. Additional MFA uses something you are (biometric, like finger prints or retina scans) for added security. 

Think of your ATM card as a token and your PIN as the password and you get a sense of MFA.

Using MFA increases security but does not guarantee it. Think of it as an additional deterrent like double locking a door with a deadbolt. 

Some accounts use text or SMS messages for authentication. This can happen when you register a mobile phone number with your account. 

Pros:

• Easy to switch to a new device

Cons:

• Relies on cellular service, which can be troublesome with international travel

• Susceptible to SIM hijacking

Authenticator apps are software-based token for MFA that uses your phone whenever you log in. While not difficult to set up, it can be challenging when moving to a new phone. You will need to know how to back up and restore the authenticator database to the new phone. 

Pros:

• Additional security specific to your device

Microsoft Authenticator

You will need a free Microsoft account to use all of the features. 

Google Authenticator

Uses a Google account. 

Yubico YubiKey and Google Titan

If an app on your smartphone is not for you, there are several hardware alternatives for a MFA token. Most are USB (even USB-C) with some Bluetooth options. 

Using a token adds to the security to computers, are not compatible with iPhones and only compatible with some Android phones. These are primarily used in business environments.

Pros:

• One of the more secure methods

Cons:

• Not universally recognized or supported; no smartphone support

• Must be set up on each device