To pre-fill the date question type via URL parameters, the value must be entered in the proper date format. While you can add text as a value, it will not be pre-filled in the response area as it only supports proper dates. The allowed date formats are shown below.
mm-dd-yy
mm-dd-yyyy
mm/dd/yy
mm/dd/yyyy
yyyy/mm/dd
yyyy-mm-dd
The field code can be used in URL parameters, as shown below.
https://example.neetocal.com/meeting-with-oliver-smith?dob=10/23/2005