If you use the User Defined Fields optional add-on module, this allows you to add any number of extra fields to a sales order that pertain to your sales orders for your business.
User Defined fields allows you to add any number of extra fields to a sales order that pertain to your sales orders for your business. To be able to edit the design of the UDF (User Defined Fields) the user needs to have the correct security access.
If any User Defined Fields have been defined on the selected Customer Billing and/or Shipping Address, any fields marked with the Transfer option will also be displayed here, for any special customer information that is important to see on sales orders. The configuration for tab names and fields from the customer will be maintained here, in addition to any UDFs created specifically for sales orders. Note that changes made to the customer UDFs after the sales order has been created will not be subsequently updated. These UDF values are editable if you need to change them from what is currently stored on the customer record.
Read the User Defined Fields manual topic for more information.