Enter or select date or current delivery period for the current invoice row. The field shows the previous invoice row's delivery period by default.
There is also a field for the delivery period in the Invoice header. If you enter a delivery period in that field, it will be used by default on the first invoice row.
The delivery period can be entered using different date formats. The date format will be converted to the format that was entered in the setting under Period Formats under the System tab in the Settings procedure.