A PDF file is usually stamped or marked or labelled
by the PDF creation software. The hidden information is stored in the
header part of the PDF file. With PDF Info, you may change PDF document
properties, including author, title, subject, keywords, creator, and
producer information. You may even add or remove hidden information.
Freeware with no advertisement, no spyware or clickbot module.
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.