This section of the configuration lets you set the reasons that will be available when a case is closed. You can also manage the email templates that will be sent out for each one. The initial values are set when creating the configuration.
Reason
The closure reason appears in the drop-down when a case manager closes a case. It will also be visible to the person who raised the case.
Description
The description should provide more information about the closure reason. It appears in the case history once a case has been closed and will be visible to the person who raised the case.
Template
This is the template inserted into the subject and body of the closure email sent to the person who raised the case. You can pick an existing closure template, or create a new one. Each reason can have a different template.
There's more information about emails and their templates in the Emails and Notifications section. Closure email templates can be managed from either section of the configuration manager.