viewController.swift

import IntentsUI

    // MARK: - Life cycle
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Call setup once at view did load
        addObservers()
        setupIntents()
    }
    
    private func setupIntents() {
        // Use extension func to allocate new user activity using inner project Shortcusts enum
        view.userActivity = NSUserActivity.with(.refreshList)
        view.userActivity?.becomeCurrent()
        
        // Code from official Apple Developer site
        // API available check. That func available only for iOS 12 and later
        if #available(iOS 12.0, *) {
            // Get all shortcuts from OS center
            INVoiceShortcutCenter.shared.getAllVoiceShortcuts { [weak self] (shortcuts, error) in
                // Find existed shortcut with activityType is equal to our inner identifier
                let refreshShortcut = shortcuts?.first(where: { (item) -> Bool in
                    return item.shortcut.userActivity?.activityType == Shortcuts.refreshList.identifier
                })
                guard let `self` = self, refreshShortcut == nil else { return }
                DispatchQueue.main.async {
                    // Add Shortcut button to view. In my case that is UITableView's footer.
                    // You can provide just UIViewcontroller's view "self.view"
                    let view = UIView(frame: CGRect(x: 0, y: 0, width: self.view.frame.width, height: 50.0))
                    self.table.tableFooterView = view
                    self.addSiriButton(to: view)
                }
            }
        } else {
            // Fallback on earlier versions
        }
    }
    
    // Code from official Apple Developer site
    // Add an "Add to Siri" button to a view.
    private func addSiriButton(to view: UIView) {
        if #available(iOS 12.0, *) {
            // Just add INUIAddVoiceShortcutButton to view
            let button = INUIAddVoiceShortcutButton(style: .blackOutline)
            button.translatesAutoresizingMaskIntoConstraints = false
            
            view.addSubview(button)
            view.centerXAnchor.constraint(equalTo: button.centerXAnchor).isActive = true
            view.centerYAnchor.constraint(equalTo: button.centerYAnchor).isActive = true
            
            button.addTarget(self, action: #selector(addToSiri(_:)), for: .touchUpInside)
        } else {
            // Fallback on earlier versions
        }
    }
    
    // Present the Add Shortcut view controller after the
    // user taps the "Add to Siri" button.
    @objc
    func addToSiri(_ sender: Any) {
        if #available(iOS 12.0, *) {
            // Setup INShortcut with UserActivity using extension function that creates a new User Activity from inner project Shortcuts enum
            let shortcut = INShortcut(userActivity: NSUserActivity.with(.refreshList))
            let viewController = INUIAddVoiceShortcutViewController(shortcut: shortcut)
            viewController.modalPresentationStyle = .formSheet
            viewController.delegate = self // Object conforming to `INUIAddVoiceShortcutViewControllerDelegate`.
            present(viewController, animated: true, completion: nil)
        } else {
            // Fallback on earlier versions
        }
    }

    // Func that configure observers to handle info about Shortcusts notifications from AppDelegate
    private func addObservers() {
        NotificationCenter.default.addObserver(self, selector: #selector(didBecomeActive), name: Shortcuts.refreshList.notification, object: nil)
    }
    
    @objc private func didBecomeActive() {
        // Do you work. For example reload data (How it in my case)
    }