Move to iOS is the official app developed by Apple that will help you make the leap from Android to iOS. (That said, why in the world would you want to do that?)
The way the app works is very simple: just follow the steps indicated by Apple, wait to receive your verification code, and type it in. That done, you'll be able to select the exact things you want to transfer: contacts, pictures, messages, bookmarks...
Move to iOS is an app that's undeniably useful for users who want to move from Android to iOS, though that decision isn't so common due to the state of Apple devices.
