PDF Annotator - the original program to work with PDF-documents. With it you can make changes to documents in this format, add captions, visually isolate some fragments, as well as add pictures. Interestingly, to add annotations to documents can be used not only the keyboard and mouse, but a graphics tablet. If your comments require more space, you can add a PDF-document blank pages and fill them. Left notes can be saved as a separate file. To view it does not require any additional software. If you need to remove all the marks in the document, it can be done with one click.