Logging out of Facebook on iPhone settings

Hi, so a while back whenever I would use Facebook for a game I would go into my iPhone settings and change to my backup email to sign in using that fab account not my personal one. Now when I go into my apple settings app there is no longer the Twitter and Facebook option to click on to sign out of Facebook on my phone Andrew not just the Facebook app. My question is how do I sign out of Facebook on my apple settings not just the Facebook app itself?