Talk:Mordor orc/@comment-71.174.25.146-20140626015359/@comment-27723099-20140626194620

In the sidebar of the editor is a field "Categories". Type the category you want to add in the text field and press enter.

Editing the categories is only possible in the normal editor, not for example on the mobile page (which has a crappy editor) or in some pop-up editors.