U can easily edit all pdf files in adobe illustrator cs versions

If you are looking for a PDF editor that will make your work easier, LightPDF is the best software for you. This is a online PDF viewer, editor and converter. It comes with all the tools you need in managing PDF files. Try it here: https://lightpdf.com/

Actually the free PDF reader, Foxit Reader can help you annotate PDFs, highline, underline, markup and add annotations will not be a problem, much faster than Adobe's product.
If you need to edit the text or any elements within PDF directly, you can try PDF Editor, works like in a word processor.