If you have upgraded to or installed Windows 10 Home on your computer and would like to upgrade to Windows 10 Pro edition to test it, then thing have become easier. Microsoft has made available for all a default product key for Windows 10 Pro that anyone can use to upgrade his or her Windows 10 Home to Windows 10 Pro, for free.
Default Product Key to upgrade from Windows 10 Home to Pro
Says Charles of Microsoft,
From your Windows 10 Home running Version 1511, enter the Windows 10 Pro Default key under change product key. VK7JG-NPHTM-C97JM-9MPGT-3V66T This default key will not activate the system, just take you to Pro so you can activate using a valid Pro key that you will provide. Once you have done this, the system will go through an upgrade process from Home to Pro, but will not be activated on Pro. You can now enter your Windows 8 Pro key into your Windows 10 Pro system and it will activate.