Data persistence is the process of storing data so that it can be accessed and used in the future, even after the user has closed the app.
One way to handle data persistence in iOS apps is to use Core Data. Core Data is an object graph and persistence framework provided by Apple. It allows developers to define the structure of their data, create and manage objects, and persist those objects to disk.
For example, an iOS app for a restaurant might use Core Data to store information about the menu items. The restaurant might define a MenuItem entity with attributes like name, price, and description. Core Data can be used to create MenuItem objects, store them to disk, and fetch them later when the user wants to view the menu.