正文：
利用 UserDefault 儲存資料

預覽圖：

程式碼：

import UIKit

class ViewController: UIViewController {
    
    @IBOutlet weak var showLabel: UILabel!
    @IBOutlet weak var enterTextField: UITextField!
    var myUserDefaults :UserDefaults!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        myUserDefaults = UserDefaults.standard

    }
    @IBAction func updateButton() {
        print("update Label")

        // 結束編輯 把鍵盤隱藏起來
        self.view.endEditing(true)

        myUserDefaults.set(
            enterTextField.text, forKey: "Label")
        myUserDefaults.synchronize()
        if let info = myUserDefaults.object(forKey: "Label") as? String {
            showLabel.text = info
            showLabel.textColor = UIColor.black
        } else {
            showLabel.text = "尚未儲存資訊"
            showLabel.textColor = UIColor.black
        }
    }
    
   @IBAction func removeButton() {
        print("remove Label")

        myUserDefaults.removeObject(forKey: "Label")

        enterTextField.text = ""
        if let info = myUserDefaults.object(forKey: "Label") as? String {
            showLabel.text = info
        } else {
            showLabel.text = "尚未儲存資訊"
            showLabel.textColor = UIColor.red
        }
    }

}