Google Authenticator is a free mobile app that provides two-factor authentication (2FA) to enhance the security of online accounts. It generates time-based one-time passwords (TOTP) that users must enter alongside their regular passwords when logging in. This adds an extra layer of protection by requiring physical access to the user’s smartphone. Compatible with hundreds of websites and services, Google Authenticator supports both Android and iOS devices. It works offline, so no internet connection is needed to generate codes. Widely used for securing email, banking, social media, and corporate accounts, it helps protect users from phishing and unauthorized access.