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 Windows Store. Select the Start button, select Settings > Update & security > Activation, and then select Go to Store.
Article ID: 12384 - Last Review: 31 Aug 2016 - Revision: 41