You can access the Mail Merge sub-module by clicking Options > Mail Merge from the LHS menu. Upon clicking this link, the Mail Merge page is displayed as depicted in the following figure:
The Mail Merge page displays the existing list with details such as Name, Description, Mail Delivery Date, and Process Status.
You can click the 
button to view the additional fields such as Source Type, Source Table/Query, Email Template, From Mail ID, To Mail ID, Process Row ID, Object SQL, Created Date, and Modified Date.