Can you explain what UserDefaults is used for in iOS development?

UserDefaults in iOS is used for storing small settings and user data that need to be preserved between app launches. It is a simple way to save data such as interface settings, flags, user preferences, etc.

UserDefaults stores data as key-value pairs and automatically saves them to disk.

Example of usage:

let defaults = UserDefaults.standard

// Saving a value
defaults.set(true, forKey: "hasSeenTutorial")

// Reading a value
let hasSeenTutorial = defaults.bool(forKey: "hasSeenTutorial")

It is important not to use UserDefaults for storing large amounts of data or sensitive information; other mechanisms like Keychain or databases are more suitable for that.