Hi Erik,
I recommend watching the video on this page about file search.
PDFs however can’t be displayed in a WooCommerce products widget – Elementor does not allow that, nor any other widget either. I guess that’s what you are trying to do, but Elementor will automatically remove them as the products widgets should only every display products and nothing else (and media files are not products).
The video tutorial on the link above will explain everything about searching files and file contents 🙂