In case you want to duplicate a campaign you can do this in the 'Actions' section in the top-right corner of the campaign page.
You can choose between duplicating your campaign using the same or new tracking points.
After this you have the possibility to edit your duplicated campaign details. You can customise the duplicated campaign as you want, for instance by changing the target group or the report period. It's always a good idea to rename the duplicated campaign, so you can see the difference between the duplicated and the original campaign.