Where within the system are different categories of data stored?

In iOS, data can be stored in different places depending on their category and purpose:

• UserDefaults — for storing small settings and user preferences.
• Keychain — for securely storing confidential data such as passwords and tokens.
• File system (Documents, Caches, tmp) — for storing user files, cache, and temporary data.
• Core Data — for complex structured data with query and relationship capabilities.
• SQLite — an alternative way to store structured data via a database.
• iCloud — for synchronizing data across the user's devices.

The choice of storage location depends on security requirements, data volume, and data type.