What is Multi-factor authentication?

In security implementation, we use Multi-factor authentication (MFA). In MFA, a user is authenticated by multiple means before giving access to a source or service. It is different from simple user/password-based authentication. The most popular implementation of MFA is Two-factor authentication. In most organizations, we use username/password and anRSAtoken as two factors for authentication. With MFA, the system becomes more secure and it cannot be easily hacked.