How-To Geek on MSN

I trust these open-source apps for all my PDF editing

Upgrade your suite of PDF tools.
Ars Technica

Why can't you open multiple files at once in Windows Explorer?

Alternatively, enter "PDF" in the search bar, highlight the files you want, then right click and select "Print". edit: I think I understand why OP is not seeing the Open option in the right click ...