https://woocommerce.com/products/woocommerce-pdf-watermark/

WooCommerce PDF Watermarks allows you to define text or image watermarks on either a global, product or variation level, meaning you have the most control over what watermarks you want to place on what products. The text watermarks can be personalised based on the customer who purchased the product by means of a template tag system, these tags are also extendible so if we don’t have a specific tag you would like you can easily add it yourself.

Changelog

* Fix: PLUGINS-2395 - Woo QI Test Issues.