How to completely log out of my Facebook account on my iPhone?

Now when I click on the Facebook icon after I have logged out the page opens and says "Logged in as ___. Continue (which if I tap this button it automatically logs me - or anyone else! - into my Facebook account) and then below this in parentheses it says "not you?"

I want to log out so that when I open the Facebook app I have to completely log in from scratch. Input my email and password manually.

So acces to yoour "Account Settings" --> "Security Settings" -- > "Recognized Devices" -- > " Your Phone and remove it

Come online from a PC or Laptop. Then change your password. After changing it, facebook will ask you a question "Do you want to log out from other devices?" Click on Yes! And you're done.