Do you have an OEM or Retail version of Windows 10? Here's how to find out.

[Windows Central]

You can quickly and easily check the type of Windows 10 license installed on your device. Here's how.
Microsoft offers Windows 10 licenses in many channels governed by different rules, but for most users, you can only acquire a license through the Retail or Original Equipment Manufacturer (OEM) channel.
An OEM license refers to the license that a manufacturer installs on new devices. If this is your case, the product key isn't transferable, and you can't use it to activate another installation. (Unless you're re-activating a new installation on the same computer.)

Full story from the WindowsCentral blog...