in the stock email app there seems to me no option once you you select an item in the trash to move it to another folder. Am I missing something?
With the Trash folder open, long-press the e-mail until you see the green checkmark to the left of the message. Then click More in the upper right-hand corner, then tap Move. You'll then get a pop-up list of places to move the message to (such as the Inbox); tap your choice.
When I press more the only options I get are "Add star" and "Mark as read"
Are you using a Galaxy S6 with the stock e-mail app?
Yes
I moved to the Blue Mail app. Does everything I needed and more. Also much quicker than the stock email client!