Explain what is meant by two-factor user authentication verification

Two-factor authentication (2FA) is a security enhancement method where a user must verify their identity using two different factors to access a system:

1. Something they know (e.g., a password).
2. Something they have (e.g., a one-time code from a mobile app or SMS).

This reduces the risk of unauthorized access, as knowing only the password is not enough — a second factor is required. For example, after entering the password, the system will prompt to enter a code from the Google Authenticator app.