It is a best practice to allow the system to add the system-generated Keyword Types to Document Types used for Document Transfer that do not already contain them. This ensures that packages can be received correctly from sending sites.
The system-generated Keyword Types are added to the Document Type as hidden Keywords. Only users with the Access Restricted Keywords privilege are able to view hidden Keywords. If the system-generated Keywords are manually added to the Document Type, they should be configured as HID(hidden) Keywords in the Keyword Options dialog of the Document Type configuration. For more information on these topics, see the System Administration module reference guide.