I want to load values saved in UserDefaults into another View

class MyData{
    // Define a singleton named for `UserDefaults`
    staticlet standard=MyData()

    // Other required features are described
    //...
}

class MyData{
    // Define a singleton named for `UserDefaults`
    staticlet standard=MyData()

    // Variables accessed by multiple view controllers are summarized together with highly relevant variables
    private(set)var allList: Item = [ ]
    private(set) var selectedList: Item = [ ]
    
    funcadd(_item:Item, isSelected:Bool=false){
        allList.append(item)
        if isSelected {
            selectedList.append(item)
        }
    }
    
    // To put a part of `allList` into `selectedList`, define it here if you need any action
    //...
}

class RegisterViewController:UIViewController {
    
    @IBOutlet weak var registeredNameLabel:UILabel!
    @IBOutlet weak var registeredDateLabel:UILabel!
    @IBOutlet var addListButton: UIBarButtonItem!
    
    // Item type → Avoid Implicitly Unwrapped as much as possible
    varitem —Item?//<-
    
    override func viewDidLoad(){
        super.viewDidLoad()
        
        // Buttons to add to MovieList
        addListButton=UIBarButtonItem(title: "Add to List", style: .plain, target:self, action:#selector(addListTapped(_:)))
        self.navigationItem.rightBarButtonItems= [addListButton]
        
        // It is better to process data from other screens with 'viewWillAppear' instead of 'viewDidLoad'
//        registeredNameLabel.text=item?.name
//        registeredDateLabel.text=item?.date
    }
    
    override func viewWillAppear(_animated:Bool){
        super.viewWillAppear(animated)
        
        guard letter item=item else {
            print("item is nil")
            // Other error handling if necessary
            return
        }
        
        // Process data from other screens here
        registeredNameLabel.text=item.name
        registeredDateLabel.text=item.date
    }
    
    @objc funcaddListTapped(_sender:UIBarButtonItem){
        print("Tapped")
        // Questions
        guard letter item=item else {
            print("item is nil")
            // Other error handling if necessary
            return
        }
        // Perform data operations only through the 'MyData' method
        MyData.standard.add (item, isSelected: false)
    }
}

classListViewController:UIViewController {
    
    // Instead of copying arrays whenever there is a change, "calculate" one of the necessary arrays each time
    var list: Item {
        switch segmentedControl.selectedSegmentIndex{
        case0:
            return MyData.standard.allList
        case1:
            return MyData.standard.selectedList
        default:
            fatalError("case cannot cover)")
        }
    }
    // Move variables accessed by multiple view controllers to 'MyData' with highly relevant variables
//    var allList: Item = [ ]
//    var selectedList: Item = [ ]
    
    @IBOutlet weak variable:UITableView!
    // Add IBOutlet to make `list` a calculated property, keep it connected correctly
    @IBOutlet weak var segmentedControl:UISegmentedControl!
    
    @ IBAction function segmentSelcted(_sender:UISegmentedControl){
        Making //`list` a computational property eliminates the need to copy arrays here
//        switch sender.selectedSegmentIndex{
//        case0:
//            list = allList
//        case1:
//            list = selectedList
//        default:
//            fatalError("case cannot cover)")
//        }
        // However, `table.reloadData()` is required
        table.reloadData()
    }
    
    override func viewDidLoad(){
        super.viewDidLoad()
        
        table.delegate=self
        table.dataSource=self
        
        // All the necessary data is stored in 'MyData' so there is no need to load it at this time.
    }
    
    If you do not call `table.reloadData()` in // `viewWillAppear(_:)`, the screen may not be updated.
    override func viewWillAppear(_animated:Bool){
        super.viewWillAppear(animated)
        
        table.reloadData()
    }
}