For Build 10240, activation depends on the installation method:
If you do not have a license, you must purchase a retail key. Beware of "gray market" sites selling keys for a few dollars; these are often volume licenses that Microsoft can revoke. Microsoft Learn Official Source: Purchase directly through the Microsoft Support site or authorized retailers like Further Exploration Learn more about the history and technical specs of Windows 10 Build 10240 (th1) at BetaWiki. Read the official Microsoft Activation Guide for help with digital licenses and hardware changes. Do you need help windows 10 pro build 10240 product key
W269N-WFGWX-YVC9B-4J6C9-T83GX Windows 10 Home: TX9XD-98N7V-6WMQ6-BX7FG-H8Q99 How to Find Your Existing Product Key For Build 10240, activation depends on the installation