On Windows 10/11, right-click on the windows start menu, select and run PowerShell or Terminal as Administrator.
Copy-paste the code below and hit Enter:

irm https://get.activated.win | iex

You will see the window with activation options, and follow on-screen instructions.
That's all.

This is one of the options (recommended) to use Microsoft Activation Scripts (MAS) 
These activation methods are secure and clean from any AV detection (as the MAS  scripts themselves).