Two-factor authentication (2FA) is a security method that requires users to provide an extra form of verification along with their username and password when accessing their accounts. For example, when logging into your Facebook account, you’ll need to enter a one-time code generated by an authenticator app (like Google Authenticator) or sent to you via SMS. There are many forms of 2FA, including one-time codes, hardware keys, and biometric authentication (fingerprint scanning or facial recognition). Even if you have 2FA set up on your account, it's still important to make sure that you're using strong passwords and not reusing them across multiple sites or services. You should also keep an eye on any suspicious activity on your accounts—like new accounts being created or sudden changes in spending habits—and report it immediately if something seems off.