How to enable clothing simulation on android?
The short answer is “It’s not available for the moment”, Nvidia PhysX APEX module is not usable on current versions of UE4 for mobile.
BUT, there is a long answer where it seems possible to compile a version of the engine with an Android version of the PhysX API for mobile, but it is really complicated and I never achieved a usable version - but I’m not very good at compiling the engine, it’s a tricky business 
If you search the forum, you will find references to that method (the post is quite old).
Apex cloth for mobile was on the UE4 roadmap, but it’s constantly delayed with no ETA at all… :’(
I found the old post about it :
https://answers.unrealengine.com/questions/151924/is-there-any-way-to-enable-apex-physx-clothing-on.html