During billing processing, you create, change and delete billing documents (invoices, credit memos, debit memos, etc.).
You can create billing documents:
with reference to a sales order
with reference to a delivery
with reference to external transactions:
You can refer to an entire document, individual items or partial quantities of items.
You can create billing documents in the following ways:
by having the system process a billing due list automatically as a background task
by processing manually from a worklist
by creating a billing document explicitly
You can also use the following forms of settlement:
by combining several SD documents into a collective billing document
by billing one or more SD documents with several billing documents (this is called an invoice split).
by creating an individual billing document for every sales document