How to Make Your Facebook Pages and Groups Completely Private
Facebook is equipped with various security and privacy settings that you can use to make the pages and groups you run completely private. You can, for example, limit participation to a certain age group, prohibit others from posting on your page or set your group's visibility to Secret so that only those invited ...
Select "About" under your cover photo and scroll to the section you would like to hide. To configure your group visibility, for example, scroll to the Groups section.