Multi-factor authentication (MFA) enhances security for Salesforce user accounts by requiring two or more forms of identification during login, as traditional usernames and passwords are no longer sufficient against cyber threats. Salesforce requires MFA for all users starting February 1, 2022, and it is available at no additional cost, utilizing methods such as the Salesforce Authenticator app, security keys, and third-party TOTP applications. Implementing MFA involves using the Salesforce Authenticator app, which integrates into the login process and requires users to have a smartphone.