I can't realise delegate pattern

Beginner in SWIFT

I have 2 ViewController and want to show in secondVC(some Label) what I wrote in firstVC(some textfield) I checked similar topics but found nothing, there is something similar with storyboard, but I don't know storyboard.

my firstVC:

protocol DataDelegate {
    func getWord(word:String)
}

class MainViewController: UIViewController {
     
    let mainView = MainView()
    var delegate: DataDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
        
        self.view = mainView
        addTargets()
    }

    func addTargets() {
        mainView.startButton.addTarget(self, action: #selector(startGame), for: .touchUpInside)
    }
    
    @objc func startGame() {
        
        guard mainView.wordTf.text!.count > 7 else {
            print("Slishkom korotkoe slovo")
            return
        }
        
        let vc = GameViewController()
        vc.modalPresentationStyle = .fullScreen
        delegate?.getWord(word: mainView.wordTf.text!)
        self.present(vc, animated: true)
    }

}

my secondVC:

class GameViewController: UIViewController {
    
    let gameView = GameView()
    

    override func viewDidLoad() {
        super.viewDidLoad()

        self.view = gameView
        addTargets()
    }
    
    func addTargets() {
       
        gameView.backButton.addTarget(self, action: #selector(dismissSelf), for: .touchUpInside)
    }
    
    @objc func dismissSelf() {
        self.dismiss(animated: true)
        

    }

}

extension GameViewController: DataDelegate {
    func getWord(word: String) {
        gameView.bigWord.text = word
    }
    
    
}

I didn't find anything similar, pls help!

You almost certainly do NOT want to use protocol/delegate pattern for this...

In general, you want to pass data to your presented controller (your GameViewController) when you create it, and then present it.

Add a property to your GameViewController to receive the data (a string, in this case):

class GameViewController: UIViewController {

    var gameWord: String = ""

    // all the rest of your code

}

Then, when you tap a button in MainViewController to call startGame():

@objc func startGame() {
    
    guard theWord = mainView.wordTf.text, theWord.count > 7 else {
        print("Slishkom korotkoe slovo")
        return
    }
    
    let vc = GameViewController()
    vc.modalPresentationStyle = .fullScreen

    // "pass" the data here
    vc.gameWord = theWord

    self.present(vc, animated: true)
}

You now have the text entered into wordTf set as gameWord in your game view controller, and you can use it however you want.