AnotherViewController.swift

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    super.prepare(for: segue, sender: sender)
  
    guard
        let viewController = segue.destination as? CustomViewController
        else { return }
    
    // compiler knows that CustomViewModel is our view model type
    viewController.viewModel = CustomViewModel(data: "hello")
}