In the field Invoicing plan under the Main tab, you can see the invoicing plan to which the invoice basis belongs. This field can not be edited. If the invoice basis is a partial invoice, to the right of the field Invoicing plan the type of the partial invoice is displayed, e.g. Advance. A partial invoice is a regular debit invoice.
Register invoices directly.
It is not possible to manually register a new partial invoice of e.g. the Advance type in Register invoices directly. These must be created either under the Invoicing plan tab in the Register Customer Order procedure or from the Standard list in the Invoicing Plan List procedure or when delivering a customer order.