"With the free Wappwolf app you have your whole photo and doc editing and sharing toolbox on the go. Reduce the number of apps in your life and be more productive. Wappwolf covers more than 25 must-have actions."
If you want to edit every aspect of a PDF, including the content and the layout, you're going to need a professional tool like Adobe Acrobat. If all you want to do is split one PDF into two, or combine two PDF's into one, I Love PDF can do the job for you.