How to have my accessibility app overlay other apps on iOS?

Question

I'm working on an accessibility app for a client and he needs it to be able to have it on top of other apps. It takes a small area and can be moved easily.

Is there an app permission or config setting to do this?

UPDATE:
An iPad owner sent me a screenshot showing a chat app floating on top of another app.

Answer 1

No, its is not possible because apple does not even give you permission to show you wallpaper too... if it does have given that feature then any app could have a possible access to some some secure data situationally.

eg: You are using payment gateway in an app now another app start running as an overlay over the existing app which means having a snap shot of the previous app as a background of your current app. Hence privacy breaching. Hence apple will not approve of something like that, hence no feature like that.

Hope this will help you to understand more clearly.