If you need to create a campaign that's very similar to one you've already used, you can make a copy. Copying a campaign creates a new campaign with the settings as the original, including the budget, targeting, conversion tracking, audiences, and linked ads.
When you copy a campaign, you can modify the campaign's features before you save it the first time.
Note: Legacy (site-based) campaigns can not be created once you use domain-based campaigns. If you copy a legacy campaign, the new campaign you create will use domains. Site and placement information in the legacy campaign will not appear in the new campaign.
To Copy a Campaign
Click the Actions button next to the campaign and choose Copy Campaign.
You can give the campaign a new name and choose a group for the campaign.
Make the changes you want, and then click Create Campaign Now to create the campaign right away or Review in Campaign Editor to make more changes before you create it.