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.
To upgrade from Windows 10 Home to Windows 10 Pro, you'll need a valid product key or a digital license for Windows 10 Pro for the device you're upgrading. You'll have a digital license if Windows 10 Pro was already installed and activated on your device.
If you don't have a product key or a digital license, you can buy Windows 10 Pro from the Microsoft Store. Select the Start button, select Settings > Update & security > Activation, and then select Go to Microsoft Store.