posting as a brand on Facebook

When you first log into Facebook, you’re automatically logged in as your profile (you, a person).

On the page (with Posting Preferences selected) – When you go to your page’s admin panel and click on “Your Settings,” you’ll see an option you can select called “Posting Preferences.” Checking this box allows you to post and comment on your page as the page identity even if you are logged in as a profile (see below).