When you open a campaign report (by clicking on a campaign name), you will get the default view of a Campaign Report:
In the top right corner, you can see an option mentioning the said Default View!
If you click on it and you don't have a saved view, you will only be able to save the current one:
If you decide to save the view, here what you'll see:
From there, you can decide to keep (or not) each part of your campaign report! Don't forget to name it, and you can save!
The menu now will let you either to Save the current view, or Use a Saved one!
You'll also notice that there is an option to get some Custom tabs - here's what you see when you click it:
In there, you can add some Widgets for a specific campaign (or several, depending on whether you did a group report or not).
These widgets will be limited to these campaigns, and they can also be saved when you save the view!