In one sentence, describe what the following article is about:

It's the white "F" on a blue background. If you aren't logged in, enter your email address (or phone number) and password and tap Log In. The search bar is at the top of the screen; typing a friend's name in will prompt a drop-down menu below it. If your friend has a post in your News Feed, tap their profile image to open their profile. It'll appear below the search bar. It should appear at the top of the "People" page that pops up after tapping their name. You'll find this option below your friend's profile picture and name. Doing so will remove your friend's notifications from your News Feed, though you'll still be able to view their profile if you choose to search for it. You may still see the post they liked if other people whom you haven't unfollowed like it as well. You can solve this problem by hiding the post itself (see below) or by unfollowing the people who liked it.

Summary:
Open the Facebook app. Type your friend's name into the search bar. Tap your friend's name. Tap your friend's profile image. Tap Following. Tap Unfollow.