Microsoft Defender is Microsoft's official app for managing Windows Defender protections on different operating systems, including Windows, Android, iOS, and macOS. This name may lead to some confusion, as it was previously used for the Windows 10 antivirus. Instead, the antivirus is now called "Windows Security," and Microsoft Defender refers to the protection management included on Microsoft 365.

From Microsoft Defender's main screen, you can check the status of your devices, including the Windows computer you're using, as well as others that you've added. You can also monitor other items such as email accounts or credit card numbers to see if they've been involved in hacks or data breaches.