Programmatically button to fullscreen?

Question

iOS

Hi all!
Can you tell me how to programmatically make a button click "Full Screen"?
All clambered nothing about it and already thought in general is it possible or not?

import UIKit
import AVKit
import AVFoundation
class VideoPlayerViewController: UIViewController
var playerViewController = AVPlayerViewController()
var player: AVPlayer?
I want to do when the device is rotated horizontally so that the player expands to full screen.
Thank you!