Customer invoice accounting records a claim against a customer and the related revenue, tax or other offsets according to the underlying transaction. A normal SAP FI customer posting maintains the customer's receivables item and updates the designated reconciliation account. The invoice, its receipt of payment and eventual clearing are distinct business events.
Begin with the business transaction
A legitimate invoice needs a customer, company code, amount, currency, appropriate posting date, tax treatment and evidence of a billable event. Some customer invoices originate in a sales order and billing process; others can be entered through permitted FI processes. A consultant should trace the real trigger before deciding which application owns pricing, approval and downstream accounting.
Understand the accounting relationship
In a simple sale on credit, the customer is debited and revenue and any applicable output tax are credited. The exact document lines depend on configuration, taxes, discounts and the business model. Customer-level accounting entries contribute to a reconciliation G/L that summarizes receivables. A second unrestricted manual G/L posting is not an appropriate substitute for the normal subledger linkage.
Illustrative invoice example
Suppose a sale has a net amount of 10,000 and output tax of 1,800. A basic illustration is debit receivables 11,800; credit revenue 10,000; credit output-tax liability 1,800. The example explains the account relationship, not a universal tax rule. The jurisdiction, tax code, accounting date and document source determine the real posting, which must be checked against the specific company's configuration.
What remains open after posting
The invoice generally remains an open customer item until a valid clearing event resolves it. Receiving money in the bank does not necessarily mean the accounting team has applied that receipt to the right document. A credit memo, reversal or partial payment has different consequences from normal settlement. Collections staff need reliable references so they can match receipts, follow up overdue amounts and avoid mistaken deductions.
A useful controls checklist
Check customer master and reconciliation-account assignment, authorized entry, duplicate references, currency, document dates, tax code, invoice support and the open posting period. After posting, compare the customer item with the relevant G/L balance at the same cutoff and scope. Where they differ, investigate special transactions, selection criteria or an actual defect; do not conceal the discrepancy through an unapproved balancing journal.
Think beyond the invoice screen
Ask what happens when a customer is wrong, a tax code changes, the billing interface fails or a payment has no matching reference. Identify whether Sales, Finance, Tax or Collections owns the correction and which audit trail proves it. Explaining those handoffs is a stronger functional skill than merely memorizing a transaction or screen.
Read next
Customer Reconciliation Accounts; Customer Business Partner Master Data; Open-Item Management; Automatic and Manual Clearing. Return to the SAP FI / FICO hub.