Memory management in an iOS app is handled using Automatic Reference Counting (ARC). ARC automatically manages the memory of an app by keeping track of the objects and variables that an app uses. When an object or variable is no longer needed, ARC releases the memory associated with it.
For example, when a view controller is dismissed, ARC will automatically release the memory associated with the view controller and any objects or variables associated with it. This ensures that the memory is not wasted and that the app runs efficiently.