Just crap
Just a junk app. Like many other "pdf creators" it's confusing, impossible to create a pdf from many images and just asks to make in-app purchases, although not explaining exactly what are those purchases for. I've bought the "PDF Box pro", what I've thought it'll gonna cover all options (because it's more expensive) - oops, my bad - it still asks me to purchase more and more. The "developer's website" it's also a joke. Apple should never allow crap like that in App Store.