get adobe acrobat... the actual program. acrobat, as apposed to just the reader, allows you to type on, cut things out, add things, insert pages, etc etc. The latest version is 6.0 and it runs a pretty penny.
From my knowledge, you can only really edit a pdf in illustrator if that is the native program it is created in. You can try illustrator again. Are you trying to type out a form?
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