The Submitted Questionnaires page displays inactive questionnaires for which you were a stakeholder. Typically, these questionnaires are inactive because you have completed the questionnaire and advanced it to the next workflow stage - generally, Review. This page allows you to follow the progress of completed questionnaires. You will not be able to view the Submitted Questionnaires page on the Home menu unless you have the Questionnaire View Submitted Questionnaires permission.
See also Using the Grid View.