Notifications are updates about activity on Facebook. You can't turn off notifications entirely, but you can go to your notifications settings to change what you're notified about and how you're notified.
Your Home Page
Learn how News Feed works, control what you see in News Feed and react to posts.
Your Profile and Settings
Learn how to add a profile picture, edit your info and manage posts on your Timeline.
Learn how to control the ads you see and how Facebook decides which ads to show you.