Mobile Gamepad turns smartphones into motion-sensing game controller
How to play Android games like PUBG Mobile with a controller
You asked: How do you use the gamepad app on Android?
S Console Gamepad for Android - APK Download
Evo Gamepad App.apk Free Download For Android_Evo Gamepad App app for android free download - apktouch.com
Astarry Wireless Bluetooth Android Game Controller Mobile Gaming Controller Gamepad Joystick Compatible for iOS/Android Phone/PC Windows/Smart TV/TV Box/ PS3(Does not Support iOS 13.4) : Video Games
Amazon.com: Mobile Game Controller, Mutop PG-9021 Mobile Gaming Wireless Bluetooth Controller Gamepad Joystick Supports Android 3.2 Above PC/System (PG-9021) : Video Games
BT Controller: Use Your Android As A Bluetooth Gamepad For Another
Senze Android/Ios Game Controller with Bluetooth - China Gamepad and Joystick price | Made-in-China.com