Two-factor authentication is a security process that requires users to provide two distinct forms of identification to verify their identity when accessing a system or service. The two factors typically include something the user knows (e.g., password or PIN) and something the user has (e.g., physical token, smartphone, or biometric identifier like a fingerprint). By combining these two layers of security, 2FA significantly reduces the risk of unauthorized access, as it is unlikely that an attacker can obtain both factors simultaneously. This method enhances the protection of sensitive information and ensures stronger authentication for online accounts and systems.