A Microsoft app for iOS and Android devices that enables authentication with two-factor verification, phone sign-in, and code generation
You cannot use a Windows 11 product key to activate Windows 10. Each version of Windows has its own specific product key requirements, and while there may have been some upgrade paths available in the past, using a Windows 11 key for Windows 10 activation is not supported. If your systems require Windows 10, you will need to obtain a valid Windows 10 license separately.