When you click the Campaigns, Lists, Reports, or Automation menu items in MailChimp's left navigation, you see drop down menus on the right side of the page.
You can create a copy of any draft or sent campaign in your account by using the Replicate option.
You can create an exact copy of any list in your account using the Replicate List option on the Lists page. Replicating a list will copy over all list settings,
With MailChimp, you can make a copy of your templates instead of creating them from scratch.