The conventional wisdom is that PDF documents are great to share because, unlike word-processing files, PDFs are in final form and can’t be modified.
If you’ve have read any part of this book, you know that PDFs are far from unmodifiable. Nonetheless, it is true that PDFs are not easily modifiable—that is, not unless you have a tool like PDFpen. Armed with PDFpen, you can make all sorts of changes to PDFs. For example:
You can fix typos in a magazine article.
You can update an old flyer, even if you don’t have the original.
You can sharpen and stylize pictures on the page.
You can redact sensitive or confidential material.
You can crop pages, or rotate them.
You can create links to other pages in the PDF, or to Web pages. ...