Multi-Factor Authentication (MFA) is a multi-step login process that provides an extra layer of security by requiring an additional factor (or factors) to be provided in the authentication process. Usually, this is done by requesting both something a user knows, such as a password, with something the user has, such as a keycard or a mobile device.
Historically, passwords have been the most common first factor, but are increasingly inadequate and easy to compromise. Because of password reuse, relying solely on a password means another organization’s security breach can become your problem. With MFA, accounts can be kept secure - even when a user’s password is compromised. An account with the password of "password" may be more secure, if MFA is used, than an account with a complicated password that is compromised. MFA is therefore one of the best “bang for your buck” ways to increase security the security of your systems.