Using Account Determination
The following figure provides an overview of account determination:

When data is transferred from the billing document to Financial Accounting, general ledger (G/L) accounts for posting sales revenue, sales deductions, and value-added tax (VAT) are determined automatically.
When processing cash sales, you must set a G/L account in the document for cash settlement (no posting to customer account).
The system can determine a reconciliation account that is different from the account that is entered in the payer master record.
When using payment cards, you also need to post to different G/L accounts.