Summary: If you are confused and have no idea to choose which Windows license key for your PC then, have a look at this article and know the Windows OEM vs Windows retail difference. This will help you in making a wise decision.
If you owe a Windows 10 operating system then you must have a Windows license key as it activates and verifies the Windows on your PC. In some cases, Windows 10 automatically get activated with a digital license instead of the product key.