Multi-Factor Authentication (MFA) Methods

**Executive summary:** This document provides an overview of multi-factor authentication (MFA) methods—including SMS, authentication apps (TOTP), email-based verification, biometrics, hardware tokens, push notifications, and social identity verifiers—explaining how each method enhances account security, their practical considerations, and associated risks (e.g., SIM swap, interception, device requirements), and recommends adopting MFA to strengthen protection of online accounts.