PrintToPDF is a shareware Macintosh printer driver that creates PDF (Adobe Acrobat) files. You do not need to have the full Acrobat package (as opposed to the Reader) installed for PrintToPDF to work. You can create PDF bookmarks to your section and subsection headings, and URLs will become hot links. PrintToPDF is not as powerful as Acrobat, but it creates simple PDFs for a much lower price ($20).
PrintToPDF has been primarily tested with Mac OS 9, but most of it should work with systems back to 7.0. Some of the Asian language functionality requires a PowerMac and the Text Encoding Converter extension. Of course, since it's shareware, you can find out whether it works well with your system and applications before paying for it. You will need Acrobat Reader 3.0 or later to view the manual and the created PDFs. To view PDFs containing Japanese, Chinese, or Korean text, you'll need the Asian Font Pack for Acrobat Reader.
OK, so you want to stamp your document. Maybe you need to give reviewers some advice about the document's status or sensitivity. This tip from author Ted Padova demonstrates how to add stamps with the Stamp Tool along with related comments.