how do I create drop down box in table but allow edit of rest of document?

I have developed a form which I need to use drop down lists – but it appears
to only work once I have locked the form to other users. I need others users
to be able to edit the form as they need to, but also to be able to use a
quick drop down list where necessary. Is it possible to make the drop down
field run without having to lock the form??