Posting an Accounting Transaction in Accounts Receivable 
The most important steps that you carry out to enter and post a document (accounting transaction) in Accounts Receivable are as follows:
The system provides you with several functions for document entry. The functions are specifically designed for the relevant accounting transaction (for example, invoices or credit memos), or to simplify the process of entering several documents of the same type.
The posting key and the reconciliation account for the customer account determine which fields are displayed on the next screen.
The system generates the document, updates the transaction figures to the account involved and, where applicable, informs you of the internally assigned document number.