What sort of editing do you want to do? Do you have a particular difficulty using the edit functions, or are you just trying to find them?
(Many kinds of edit are not feasible).
Same question, except that all I need to do is increase the size of the text. Is that not possible through acrobat?
It depends on what kind of text it is, what kind of document, etc.
In principle it should be possible to do it using the Edit Text & Images tool, under Tools - Content Editing.