PDF Viewer is a free application, available for iOS and Android mobile devices, that allows users to view and annotate PDFs with ease. PDF viewer is unique in that it allows users to edit documents, e.g. delete pages, rotate pages, and add images and notes, and even add signatures, on any mobile device. Users can also easily check out a list of all recent annotations and edits, facilitating easy collaboration. PDF Viewer will be of use to anyone looking to quickly and easily collaborate on documents, and may prove especially helpful for the classroom or office.