Does the Save as PDF WordPress plugin cache generated PDFs?

No. The plugin creates a new output file when the visitor clicks the button. This keeps the output in sync with the current page, plugin settings, and visitor-specific content.

Why the plugin creates a fresh file

A generated file can depend on the page content, selected plugin options, logged-in visitor, form values, filters, language, or what the visitor changed before clicking the button. Creating a fresh file avoids serving stale or incorrect output.

About WordPress page caching

A normal WordPress page cache can make the web page load faster, but it does not make the plugin reuse a previously generated file. In Content mode, page caching can also interfere with what the button captures from the page, so do not treat page caching as output caching.

If you need to reuse generated files

Reusing generated files requires custom site logic. The PDF Created Callback option can save the generated file after conversion, but it does not by itself make future button clicks reuse that file.

Your site would also need custom logic to decide when the saved file is still valid, serve it to visitors, and regenerate it when the WordPress content or plugin settings change.

If your real problem is speed

If you are asking about caching because conversion feels slow, use the performance FAQ instead: Why does WordPress PDF conversion take several seconds?.