MFA

Multi-factor authentication (MFA) is the process of authenticating an identity into a computing system, application or service by providing at least two of the following authentication factors:

What you know (password or secret key)
What you have (smart card or hardware token)
What you are (biometric data)

The following list provides the most common MFA factor implemented today by security companies:

Biometrics.
Magnetic stripe cards.
Security keys.
Security tokens/mobile devices.
One Time Password (OTP).
Challenge/response.
Smart cards.