Hello, thank you for reaching out.
If you have a Windows 11 Pro product key but are currently running an Evaluation edition, you’ll need to perform a clean installation of Windows 11 using bootable USB installation media, then use your Windows 11 Pro product key to activate it.
You can create bootable USB installation media using the Microsoft Media Creation Tool (MCT) -
https://www.microsoft.com/en-us/software-download/windows11
For reference, see -
https://www.microsoft.com/en-us/windowsinsider/cleaninstall
During the installation, enter the 25-character Product Key you have for Windows 11 PRO and then click 'Next' to start the Installation.
Let me know if you still need more help.