iPhone/iPad- Notifications

Notifications are pop up messages that give you information about something
taking place when the app is closed.

You can control each app and which ones you would like to send you Notifications.
There are three different types of Notifications
1. Sounds- when enabled this will send you a ring when you have one
2. Alert- this will send you a message as in the form of a text message
3. Badge- this will put a number in the top right hand corner of the app
Settings > Notifications

Take Facebook for example. Here I got an alert that my friend sent me a message.