Watermark On Pdf can add watermarks to all or some pages of a PDF file. If you then secure the document with a password to prevent changes, it can't be removed
In this section: Using Watermark On PDF Watermark On PDF is an add-on for Microsoft Office Word that allows you to add watermarks to all or some pages of a PDF file. You can use watermark on PDF in Microsoft Word 2007 or later to add watermarks to a PDF file for all visitors to your site that share your PDF file. Note that watermark on PDF doesn't work if the PDF file is protected with a password. Use Watermark On PDF In the previous section, we saw that you can add watermarks to a PDF by using the Add Watermark to PDF wizard. To add a watermark to a PDF file in Microsoft Word 2007 or later, use the Add Watermark to PDF wizard. On the Add Watermark to PDF wizard page, select the Watermark option as shown. Note that there may be a box in the Add Watermark to PDF wizard.