However, WatchKit allows you to add more functionality to the notification system, and go beyond simply displaying a message. This means that you don�t need to take your phone out of your pocket when you feel it vibrate instead, you just need to quickly look at your watch. If you don�t do anything, the watch simply displays the notification message (if one is present) alongside the iOS application�s icon. With an Apple Watch, notifications that appear on the phone are also displayed on the watch. These notifications are generally limited in terms of what they can do: they can display a message, play a sound, and also update the badge number on the application�s icon.
When you receive an email, iMessage, or tweet, applications on your iPhone have the ability to show a notification on the screen.
