If your Magento orders have a delivery date, enter the name of the (extension) attribute that holds it. The date is then included when orders are synced.
Leave it empty if you don't use a delivery date.
Good to know
The date must be in Magento's standard format: yyyy-mm-dd hh:mm:ss.
Type the attribute exactly as it is named in Magento – same spelling and same upper/lower case.