Based on Admin Site settings, the Signature Date(s) field will be passed to the doc providers as the application date. If this field is used for the application date then it will be required prior to submitting any doc packages.
If this field will not be used as the application date then it can be left blank and the application date will populate from the 1003 > Government Monitoring Tab > Interview Date.
Tip: Site Administrators can help identify which field must be filled out for the application date.