Recording screen and user inputs (gestures) on iPad
You can program your app so that it shows the gestures on screen - then it would appear in the recorded video as well. You would then have a simple switch in your program's source code so that you can enable this feature only for demonstration videos and not in the actual released app.

Many modules exist for doing this easily - for example:


Swift: TouchVisualizer
Obj-C + Swift: COSTouchVisualizer
Obj-C + Swift: Touchpose
Obj-C + Swift: Fingertips


A less sophisticated solution is to use the built-in accessibility features of iOS. You can read a guide on doing that here.