Issues with editing existing files with Acrobat XPro

Edit options are only available when the file allows editing. In Acrobat X, you need the font that's used in the text you are editing to be available on your system. With Acrobat XI and later, you can change the font on the fly if you don't have the exact font available.

What exactly do you mean by "edit"? You are referring to forms, are you planning on editing form fields, or a static document? What problems are you running into? Acrobat X has a different user interface than Acrobat 9 and earlier, but all the functionality that you had with an earlier version of Acrobat should still be there.