AR begins with the customer master (in S/4HANA, a business partner in the customer role). Just as AP depends on accurate vendor data, AR depends on accurate customer data: every invoice, payment, dunning letter, and credit check reads from this record.

A customer master record has three levels, mirroring the vendor master:

• General data — valid company-wide: name, address, country, tax numbers, and the business partner number. Shared across all company codes.
• Company code data — financial settings for one legal entity. The pivotal field is the reconciliation account, the G/L account that automatically receives the offsetting entry for every customer posting. Payment terms, dunning procedure, and payment methods also live here.
• Sales area data — used when the customer is sold to through Sales and Distribution (SD): sales organization, distribution channel, shipping and pricing details.

Fields an AR clerk uses constantly include payment terms (which set the due date and any early-payment cash discount), the dunning procedure and dunning level (controlling how overdue customers are reminded), and credit-related settings. A dunning block can suspend reminders for a customer under dispute.

To maintain a customer in S/4HANA you use transaction BP (Business Partner). In classic ECC the codes were XD01/XD02/XD03 (create/change/display centrally), FD01/FD02/FD03 for the accounting view only, and VD01 for the sales view.

Accurate addresses and tax numbers ensure invoices are valid; correct payment terms ensure due dates and discounts are right; and a well-set dunning procedure ensures overdue accounts are chased automatically.