Here's where you might find all the PDFs you have downloaded on your devices:

Desktop Computers (Windows, Mac):

Default Download Folder:

On Windows, is usually located in the "Downloads" folder. You can try to locate it by opening File Explorer and then going down to the Downloads folder.

On macOS, it is located in the "Downloads" folder inside your user directory.

Browser-Specific Settings:

Some browsers let users set a custom default download location. You can check your browser's settings to see if you've moved it.

Mobile Phones (Android, iOS)

File Manager App

Open the File Manager application.

Now look for "Downloads."

Browser App

From the Download history or settings of the browser, look if the downloaded PDF is there

If you still can't find it, use these additional hints

Search from device: You can search for the PDF file using the name or related words.

Check for it in your cloud storage: If you use a cloud-based service such as Google Drive or Dropbox, it might have automatically synced the PDF there.

Check download history in your browser: Sometimes, most browsers keep download history which will be useful in finding the downloaded file recently.

Try to look out for your PDF files in any of these above places.