mitcho (Michael Yoshitaka Erlewine)

This plugin adds a big red “preview” watermark to post previews. Never again be confused whether you’re looking at a preview or a published post!
Note: This plugin may not work well if your theme involves a background image on your <code>body</code>.
This plugin is a component of the <a href="http://ecs.mit.edu" rel="nofollow ugc">MIT Educational Collaboration Space</a> project.

Distinct Preview

This plugin adds a big red "preview" watermark to post previews. Never again be confused whether you're looking at a preview or a publi …

Little Package

Canyon Webworks

PDF Ink Lite adds watermarks and password protection to every PDF your customers download from WooCommerce, Easy Digital Downloads, and Download Monitor. Watermarks can include customer-specific data like names, emails, and date, and are customizable with font face, font color, font size, vertical placement, and text.
PDF Ink Lite is the only free watermarker for WordPress which includes necessary libraries (so you don’t have to ask your host to load them), and watermarks newer versions of PDFs (not just older versions).
<h4>Features:</h4>
<ul>
<li>Choice of font face, color, size and placement (a horizontal line of text, centered anywhere on the page)</li>
<li>Included font types cover most languages, and the plugin is internationalized</li>
<li>Dynamic customer data inputs (customer first name, last name, email, order paid date, and phone) to customize PDFs on-the-fly</li>
<li>Add a password to your PDF, and/or anti-copy, anti-print protections</li>
<li>Watermark only designated PDF downloads (as specified by you), or all PDF downloads from your site</li>
<li>Watermark is applied to all pages of the PDF (<a href="https://pdfink.com/" title="Upgrade to the full version" rel="nofollow ugc">upgrade to choose pages</a>)</li>
<li>Accommodates different page/paper sizes, and PDFs with various page sizes (letter, A4, legal, etc)</li>
<li>Secure & encapsulated: PDF Ink hooks into e-commerce download link clicks and checks for PDFs and maybe marks them – that’s it!</li>
</ul>
For better PDF coverage and many more options, <a href="https://pdfink.com/" title="PDF Ink" rel="nofollow ugc">check out PDF Ink, the full version of PDF Ink Lite</a>.
<h4>Upgraded (paid) version features:</h4>
<ul>
<li>Clean, robust settings panels and a separate watermarking testing suite</li>
<li>Watermark all PDF files with same settings OR set individual watermarks/passwords per product or even per product variation</li>
<li>Begin watermark on selected page of PDF document (to avoid watermarking a cover page, for example), and/or select end page</li>
<li>Watermark every page, odd pages, even pages, or ranges of pages</li>
<li>Unlimited rotatable watermark locations on one page, anywhere on the page</li>
<li>Additional dynamic customer data input (business name, address, order number, product name, quantity of product purchased), and filter hooks for adding your own</li>
<li>Semi-opaque (transparent) watermarks – hide your watermarks completely if desired</li>
<li>RTL (right to left) watermarking</li>
<li>Use of some HTML tags to style your output, including text-align CSS styling (right, center, left is default), links (<a>), bold (), italic ()…</li>
<li>Additional text formatting options, such as font color and style (bold, italics) using HTML</li>
<li>Line-wrapping, forced breaks with and tags</li>
<li>Upload and use your own font for stamping. Also, hooks to further customize font use</li>
<li>Higher level PDF protections with AES encryption and extended file protection settings</li>
<li>Keep original and/or add file metadata</li>
<li>Edit or add PDF annotations, add embedded streams, and edit PDF outgoing (URI) links</li>
<li>Open ZIP files and mark PDF files inside the archive</li>
<li>Works with EPUB! Stamp EPUB files with customized text</li>
<li>Shortcode for creating PDF download links for any page (no need for e-commerce plugin)</li>
<li>Embed marked/encrypted files on the page, using ADOBE SDK embed or PDF Object JavaScript embed.</li>
<li>Test watermark and/or manually watermark a file on the fly, from the admin panel</li>
<li>Preserves external embedded PDF links despite watermarking; internal links (ToC) are not reliably preserved (<a href="https://pdfink.com/?source=wordpress" rel="nofollow ugc">add SetaPDF-Stamper to PDF Ink</a> for this feature)</li>
<li>Filter hooks to add 1D and 2D barcodes (including QR codes)</li>
<li>Remove stamped files from your server after stamping, or on a schedule</li>
</ul>
<a href="https://pdfink.com/" title="PDF Ink" rel="nofollow ugc">PDF Ink is priced below competitor plugins that offer maybe half the function.</a> Why? Because we want you to succeed! 🥰

PDF Ink Lite – Free PDF Watermark & Password Protection

Watermark and password protect PDFs with WooCommerce, EDD, and Download Monitor. No Ghostscript required, PHP 8+ compatible. Since 2014 (FKA WaterWoo)

Distinct Preview vs PDF Ink Lite – Free PDF Watermark & Password Protection