Bitwarden is an open-source password management service that securely stores and manages sensitive information, such as passwords, passkeys, and credit card details. It offers a range of client applications, including a web interface, desktop applications for Windows, macOS, and Linux, browser extensions for major browsers, mobile apps for Android and iOS, and a command-line interface. Bitwarden provides both a free cloud-hosted service and the option for users to self-host their own server, ensuring flexibility and control over data storage.