provided that you grant the necessary permissions to it when you sign up for the app or website in question. Every app that you try logging into using your Facebook account will initially ask you ...

You can log into Facebook on your computer or phone using the website or app. Once you've logged into Facebook, you can save your account information and log in ...

Understanding OAuth: What Happens When You Log Into a Site with Google ... mentioned MyPermissions. A lot of apps want access to your Facebook account so they can integrate social features.