UIStoryboard load from app delegate

From your code I see UIWindow object is not initialised.

You need to initialise it if you don't mention any Storyboard Name in App-Info.plist.

Also, make the Window key and visible. Please change your code as displayed below:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window=[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    UIStoryboard *storybord = [UIStoryboard storyboardWithName:@"MainStoryboard_iPhone" bundle:[NSBundle mainBundle]];
    UIViewController *vc =[storybord instantiateInitialViewController];
    [self.window addSubview:vc.view];
    [self.window makeKeyAndVisible];
    return YES;
}

For Swift 4.2 and higher.

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    window = UIWindow(frame: UIScreen.main.bounds)
    let storyboard = UIStoryboard(name: "YourStoryboardName", bundle: Bundle.main)
    let viewController = storyboard.instantiateInitialViewController()
    window?.rootViewController = viewController
    window?.makeKeyAndVisible()
    return true
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{

   UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard_iPhone" bundle:[NSBundle mainBundle]];
   UIViewController *vc =[storyboard instantiateInitialViewController];

   // Set root view controller and make windows visible
   self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
   self.window.rootViewController = vc;
   [self.window makeKeyAndVisible];

   return YES;
}

Try this. I think is missing set root view controller and make windows visible.