I have a word document on my MacBook, I airdropped it to my iPhone but Microsoft Outlook keeps opening it as an attachment in a new email. I want to save the file to my phone, not open in Outlook. How do I change this?

In Xcode, there is a keyboard shortcut to hide the navigator, ⌘,0. But it stopped working. I went to system preferences and manually added it back a few days ago but it disappeared again today suddenly. Why does this keep happening?

I am reading the free book from Apple Education titled "Develop In Swift Fundamentals". I am on the chapter titled "Controls In Action" and the section of the chapter I'm stuck on is titled "Programmatic Actions" (page 287). The section has me connect a UIButton programmatically by first manually typing in @IBOutlet var button: UIButton! then connecting the button using this code below. button.addTarget(self, action: #selector(buttonTapped(_:)), for: .touchUpInside) I pasted the code above right after the viewDidLoad function, however I get a fatal error. Thread 1: Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value I've attached a link to the Github repository if you want to download the code and run it in Xcode. [https://github.com/campusgateapp/CommonInputControls) import UIKit class ViewController: UIViewController {     @IBOutlet var toggle: UISwitch!     @IBOutlet var slider: UISlider!     @IBOutlet var button: UIButton!     override func viewDidLoad() {         super.viewDidLoad()         button.addTarget(self, action: #selector(buttonTapped(_:)), for: .touchUpInside)     }     @IBAction func buttonTapped(_ sender: Any) {         print("Button was tapped!")         if toggle.isOn {             print("The switch is on!")         } else {             print("The switch is off.")         }         print("The slider is set to \(slider.value).")     }     @IBAction func switchToggled(_ sender: UISwitch) {         if sender.isOn {             print("Switch is on!")         } else {             print("Switch is off!")         }     }     @IBAction func sliderValueChanged(_ sender: UISlider) {         print(sender.value)     }     @IBAction func keyboardReturnKeyTapped(_ sender: UITextField) {         if let text = sender.text {             print(text)         }     }     @IBAction func textChanged(_ sender: UITextField) {         if let text = sender.text {             print(text)         }     }     @IBAction func respondToTapGesture(_ sender: UITapGestureRecognizer) {         let location = sender.location(in: view)         print(location)     } }