But to put an app back on your home screen, you’ll have to go to the App Library. Once there, search for the program, long-press on it, and select Add to Home Screen.

With iOS, new apps get a spot on the home screen automatically. If there’s an app in the App Library that isn’t on the home screen, tap and hold on its icon until it starts wobbling, and then ...

To exit this app-management mode, press the home button. This is what seems to have happened with my friend — the Mail app had somehow gotten tossed into a new, blank home screen.

Hold your finger down on the app you want to place on your Home screen. When the app icon grows larger, drag your finger across the screen and you'll notice the app follows.