Control F on Preview

Why not use Spotlight, either by itself, or from a Finder window's search field, to locate those PDF containing a common word. You never have to open those PDF in Preview at all until you narrow your search results:

kind:pdf misfits
kind:pdf "here's to the crazy ones."

and if you wanted to find those PDF with a common word and keyword

kind:pdf keyword:mykeyword misfits

madihah12 wrote:

Is there a way to find a word on preview across multiple documents opened, without control F each of them, but just once?

Command F is the default search short-cut.

If you have Preview.app> Preferences> you can make changes to have all images open in one window.

( Option Command 2 will show the thumbnails )

Not txt files or PDF.

It is hard to believe you can search ever open file that is not the active window.

Preview User Guide for Mac - Apple Support

Spotlight—

Narrow your search results on Mac - Apple Support

Even in Finder>Preferences>Advanced> current folder is limited to file name, not content.

you can submit your Apple Feedback http://www.apple.com/feedback

leroydouglas wrote:

Even in Finder>Preferences>Advanced> current folder is limited to file name, not content.

Sorry? Finder search is extremely powerful and flexible. What makes you think you can only search by file name in the current folder???