The open items of an account can only be cleared once you post an identical offsetting amount to the account. In other words, the balance of the items assigned to every other must equal zero. Throughout clearing, the system enters a clearing document number and the clearing date in these items. In this way, invoices in a vendor account are indicated as paid, and items in a bank clearing account are shown as cleared.
You usually use the payment program to clear invoices. Manual clearing of open items is therefore not usually necessary. Though, you will sometimes have to clear items manually if, for example, you receive a refund from your vendor or you have set up a direct debit procedure.