Outgoing payments may be issued for vendors, customers, or accounts. When creating an outgoing payment for customer or vendor, the list of open documents and transactions are listed on the payment form, and you just have to choose the ones to be paid. Technically, you can create a single outgoing payment for paying the entire list of open transactions and documents of the given business partner. If such use-case is not a common practice in your business, you can set the maximum number of documents or transactions to be paid by a single outgoing payment:
When a user attempts to add an outgoing payment where greater number of documents or transactions are selected, an error message appears and the action is blocked. By default, the value “0” is displayed in this field, and the number of documents to be included in single outgoing payment is unlimited. You can change this setting at any time.