https://www.archie.tw/ios-user-interface-default-value

ViewController.swift

class ViewController: UIViewController {
    @IBOutlet private weak var nameTextField: UITextField!
    @IBOutlet private weak var passwordTextField: UITextField!
    @IBOutlet private weak var addressTextField: UITextField!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        setUpView()
    }
    
    private func setUpView() {
        nameTextField.placeholder = "給值"
        passwordTextField.placeholder = "給值"
        addressTextField.placeholder = "給值"
    }
}