By default, a delivery date is required during the order creation process. Optionally, you can easily disable and hide this field on the Order/Invoice Settings page.
First, click on Order/Invoice Settings under Configurations menu category. From there, you can choose None, Delivery or Ship from the Use Delivery or Ship Date drop-down. Click on Update once done.
If the setting is "Delivery" or "Ship", you'll need to select a valid delivery date when creating an order for a customer and the customer will need to select a valid delivery date when making an order in your B2B Customer Portal.
If the setting is "None", the delivery date field will not be shown on the order page.