How do I add, remove or edit text on a pdf file using Acrobat 9?

[liljoentx]

Formerly, on this same computer, several weeks ago, I was able to "activate" a .pdf file, using this same Adobe Acrobat 9, by simply selecting what I best recall was an option under the Document tab in the Menu Bar. That option no longer is available for some reason.

My question is how do I once again "activate" a .pdf file I just downloaded, so that I might edit its fields, by adding or removing text from them? Please advise?

[try67]

Does it happen with all files? Including ones you were able to edit in the

past?

[liljoentx]

I opened one I did the other day and it had a purple bar across the top of the page with a button at the left which said "Highlight fields," which I clicked and the same purple bar and button suddenly appeared on this new document. Some of the important fields seem to be still locked, but it did highlight  bunch which hadn't shown up as available before. Thanks for that portion of it, anyway! Maybe that will indicate something else you can suggest!

[try67]

Sounds like the file you were trying to edit is locked or secured or something like that, which prevents it from being edited in Acrobat.