After an instance is created, you can add a description.
Alternatively, click the instance name to go to the Basic Information page. In the DB Instance Information area, click in the Description field to edit the instance description.
The instance description can contain up to 64 characters, and cannot start with and end with a space. Only letters, digits, hyphens (-), underscores (_), periods (.), and spaces are allowed.
Alternatively, view the results on the Instances page.