If you've already purchased Windows 10 Pro and need to find your product key, you might check:
: If you have a valid product key, you can activate Windows 10 Pro by going to Settings > Update & Security > Activation. Click on "Change product key" and enter your key. windows 10 pro activation key 64 bit txt
Generic Product Keys to Install Windows 10 Editions | Tutorials If you've already purchased Windows 10 Pro and