I have created an SMS app in Xcode (Swift). The user will go to the app's settings menu by pressing a button.
Here is the code for the button:
UIApplication.shared.open(NSURL(string: UIApplicationOpenSettingsURLString) as! URL, options:[:], completionHandler: nil)
There's nothing you can do in your own app. The call to
open launches another app and leaves your app.
iOS provides two simple ways for the user to return to your app.