Choose Move at the top of an Idea Workspace on the website, or Move to another team in its action menu in the mobile app, then choose the team it belongs in. Its items, lines and images go with it and its address stays the same. Members of the destination can open it; members of the team it left lose access unless they are also in the destination.
You can move an Idea Workspace when you can change it and can add work in the destination. The move is refused when the destination's plan has no room for another Idea Workspace or for the number of items in this one.