That seems unusual. However, I found a workaround that can function the same way as Open with. That's including Word app in Send to list.
If it's okay with you, here's how:
- Click start then locate Word app
- Right-click > More > Open file location
- Copy the shortcut file
- Press Windows key + R then enter this:
shell:sendto
- Paste the Word app shortcut in that folder
Now, when you right-click on a PDF file, just hover on Send to and you'll find the Word app on the list. It should function the same way as Open with