When you login, you will be presented with the list of surveys that you have already created. Toward the right hand side there are links to Copy, Edit and Delete each survey. Click on the Copy icon to make a copy of the survey.
An identical copy of the original survey with all the questions and formatting will be created for you.
Screenshot
The copied Survey is not functioning like the original survey?
Although most of the branching / logic is copied over, you may have to reset the logic / branching for some questions. When you copy a Survey: please test it and update the logic wherever necessary.
The copy of the Survey will be placed in the Main folder. Once the Copy is created, you can rename it and move it to any of the folders that you have in your account.