But once you have 2 accounts on 1 iPhone that are completly seperate you should use an additional app like “Friendly” to avoid the hasle of signing in and signing out of Facebook constantly. Installing the Friendly Social app. Open up the App Store on your iPhone and install Friendly Social, which is a free app that can be downloaded right …
https://iphone-tricks.com/tutorial/3431-how-to-use-multiple-facebook-accounts