Usually, you'd activate Windows 11 (or 10) using the Settings app to enter the product key. However, if you're in an enterprise environment and you have a specific type of activation key, you can ...

To fix Activation error 0x8004FC12 on Windows 11/10, use the FSUTIL command to clean up excess old Transactions on your PC. More suggestions here.

Should you activate Windows? While it's completely safe to use Windows 10 or 11 without activating, I wouldn't suggest doing that because there are plenty of benefits to getting a licensed version.

Guide to fix Windows 11/10 Activation or Update Error 0x800f0805. Depending on which situation you are in, follow those solutions here.

Microsoft's official Windows activation methods involve either the customer entering a 25-character product key when prompted, or signing in with their Microsoft account to apply a digital license.