It's also important to be sure you're using Acrobat and not Reader. You cannot edit pdfs in Reader, and it will be fairly easy to tell that that a pdf is editable if you are in Acrobat just by clicking around.
You cannot edit pdfs in Reader,
That depends on how they define "edit" (which I ask about in the linked thread).
They could just be talking about filling in fillable form field for all the info they gave us.
True! Definitions are crucial. I assumed they meant editing beyond filling in forms, because form fields are indicated by the text cursor in Reader. I should have been more thorough in my answer.