This feature is for premium members only. It allows the team users to duplicate projects and share/edit with the rest of the team members.
Click on a project and select Duplicate URL.
A window will pop up with a link, click on Copy to duplicate the URL.
Now you can share the project with your team members in variety ways. Just paste the link and send to them.
They can click on the link or copy and paste the link in a new window. It will have a pop up window ask you to Create New project. After change the name, click on Continue.
The project you shared with your team member will appear in their account as a duplicated version.