I scrolled down the page and noticed that you have an available app for mobile users. I decided to download it so that I'd be able to check my answers and also to answer some questions through my mobile. However, as soon as I downloaded the app, I tried to log in my account, only to realize that there is no function of logging in by Facebook, so how am I supposed to log in my account since there is no such feature? Is there any other way? My account is only accessed through Facebook — is there any way to create a password to the account so that I can log into my account through that pass?
There is a discussion on the overall StackExchange Meta that explains that you have to have the official Facebook app installed:
I don't use Facebook, so I can't test to see if anything has changed since 2014 when the question was was asked but I think it should work.