Before upgrading to Windows 10 Pro, make sure your device is up to date and running the most recent version of Windows 10 Home.
For more info about how to keep your PC updated, see Windows Update: FAQ.
Upgrade using a Windows 10 Pro product key
1. Select the Start button, then select Settings > Update & Security > Activation.
2. Select Change product key, and then enter the 25-character Windows 10 Pro product key.
3. Select Next to start the upgrade to Windows 10 Pro.
Having issues with activation after your upgrade?
See the following for more help activating your valid product key or digital license for Windows 10 Pro: