The Unreal Engine 4 is suports Android and iOS “natively” but the windows 10 MOBILE not, however the Epic Games team announced that UE4 now suports UWP APIs. I want to create a mobile game only for Windows 10 Mobile with that engine, but I never saw an app or game in UE4 in Windows store. It’s really possible to create a game only for smartphone with windows 10 mobile with Unreal Engine 4?
From what i just happened to see it appears the UWP code is only available from github right now and not part of the actually released engine yet…hopefully eventually it will be. Check out this post for more details on the UWP option.