There are many types of notifications with many features. The status bar is a type of notification it appears as an icon in the status bar. We can swipe the notification bar to see it. Heads-up notification is also a type that appears when we get a notification and then it disappears. Lockscreen notifications which we can see through the lock screen and sometimes we get popups. App icon badges are like users having to long press on that respective app to see the notifications of that app. In this way we can get our notifications on the sleeping screen in case of mobile phones.