Document Number Assignment
In the SAP System, every document is assigned a number that identifies it uniquely within a fiscal year and company code.
There are two types of number assignment:
The accounting clerk enters the number of the original document during document entry, or the number is transferred automatically from a pre-invoicing system. A prerequisite is that the document numbers are unique. The system checks whether the number entered already exists and prevents users from assigning the same number twice. Numbers assigned to documents that have been archived however, can be reused.
The system automatically assigns a sequential number. The accounting clerk transfers this SAP document number to the printed original document and then files it using this number. This method is used if the original documents do not have a unique document number. This is the case, for example, with vendor invoices.
You use a number range to define how the document number is assigned. Each document type has a specific number range from which the document number is selected.
When you reverse documents, the system automatically assigns a number for the reverse document. To do this, the system requires a document type that has internal number assignment. Every document type with external number assignment must therefore be assigned a reverse document type that has internal number assignment.
Documents posted with a document type that has internal number assignment are reversed by the system using the same document type if you do not specify a separate reverse document type.
Sales and Distribution (SD)
If you have installed the Sales and Distribution (SD) component, your system administrator can configure the system so that either the invoice number from SD is used for the accounting document, or separate document numbers are assigned to invoices from SD. For more information, see the SD - Sales and Distribution documentation Number Assignment for Material Master Records and Validity Period for the Document Number Interval