How do I copy multiple fields from one form to another?

Try using the Field Manager App.

https://apps.jotform.com/app/field_manager

This should allow you to copy/clone multiple fields from one form to another.

This should work. Is there a way to access is directly from JotForm?

The only way to access the app (and all other apps) is through their direct link. You can find all the apps we offer on this page https://apps.jotform.com/

For your convenience, here's the direct link to the Field Manager App http://fieldmanager.jotform.io/

I recommend you bookmark that page on your browser for easier access in the future if needed.