Deactivating a Campaign limits Users from creating new Events and essentially closes the Campaign. Depending on a User's permissions, you may still be able to edit Post Event Recaps, update Campaign Goals, reactivate the Campaign, and more.
To Deactivate a Campaign, simply click the "x" button underneath the Campaign Name.
A lightbox will appear, prompting you to confirm deactivation. Select "OK". Your campaign has now been deactivated.