Yes .
Can you make UE4 games which run on mobile phones
Take a look through the documentation for mobile development to get started here. Epic also have some great video tutorials for mobile development from their Twitch stream hosted on Youtube here.
You can also download example projects in the Unreal Editor that Epic have published on Google Play and the App Store for educational purposes, such as Tappy Chicken and Match 3, to take them apart and see how they go work. You can also find examples of commercial games made for mobile with UE4 on Epics website here.