Search searchable PDF documents

This is not currently possible out of the box.

If you have a license to use M-Files Discovery, one potential approach is to configure it to search for PDFs that contain no machine‑readable text (for example, using the regex (?<value>.\n) with inverted match).

In general, it's best to ensure that documents are OCR‑processed as needed when they are imported into the vault. For example, if you are importing files through external file sources, you can enable the Searchable PDF options to automatically OCR them.