In notifications you can see the following information: friends event, activity on your wall, activity on your post, mentioned event and received new message.

To check your notifications:-

For Desktop:

1. Click on the Notifications icon on the right of the top bar
2. Click on View All button:

For Android:

You receive your notifications as push notifications but you can check all received notifications any time.

1. Tap on Notifications icon  in below menu bar.

3. If you want to check all notifications from the exact category tap on the View All button.

For iOS:

You receive your notifications as push notifications but you can check all received notifications any time.

1. Tap on Notifications icon  in below menu bar.

3. If you want to check all notifications from the exact category tap on the View All button.