You can use a plugin like Rankmath or Yoast to automatically redirect all image permalinks to the actual image files. If you want to redirect a specfic image permalink to a custom URL, you can use a plugin like Redirection (or the native redirect feature in Rankmath) or, if you don't want to add plugins, add a custom redirect in your .htaccess file.
If you want to change the URL to the actual .pdf file, you need to move the file using the file manager in your hosting control panel, a ftp client or a plugin like "File Manager". If you want to change the permalink for the pdf file "page", just use the same method as for images.
