If you have a valid Windows 10 Enterprise product key, you can activate Windows using these steps:
Click on the Start Menu and then select "Settings" (the gear icon).
In the Settings window, select "Update & Security."
In the left sidebar, choose "Activation."
Under "Activate Windows," click on "Change product key."
Enter your valid Windows 10 Enterprise product key and then click "Next."
If the product key is valid, Windows will activate. Follow any on-screen instructions if prompted.