In what cases does the instance of a controller get initialized?

An instance of a controller (UIViewController) is initialized in the following cases:

• When creating a new screen or interface component programmatically, for example, through MyViewController().
• When loading from a storyboard or xib file, when the system calls the init(coder:) initializer.
• When transitioning between screens (for example, via segue), when the system creates a controller to display a new interface.

Initialization occurs before the view loads, usually at the moment of preparing to display the controller. After initialization, lifecycle methods such as viewDidLoad are called, where you can set up the interface and data.