At the bottom of every page on Facebook, there's a link named Privacy. Clicking this will take you to a page entitled “Controlling how you share” which provides useful advice on Facebook’s security settings and has a link which allows you to Edit your privacy settings.
Facebook makes some information, including your name, profile picture, gender and networks available to everyone and you cannot make this information private. You can use the Preview my profile button on any privacy settings page to see how your information appears to others.
Be careful about allowing people to become your friend on Facebook. Once you have accepted someone as a friend they can access any information that you have marked as viewable by friends. Remember that you can remove friends at any time and that you can restrict people’s access to your profile by making them limited friends.
Facebook also shares information with websites and apps, including search engines. You can remove any apps you don't want to use or turn off platform completely. If you do this you won't be able to use any platform apps or websites and Facebook won't share your information with them.