You need to complete the following customizing tasks on the sender system before sending cash flows to an SAP S/4HANA Cloud Treasury workstation: activate individual source applications and rebuild flow types in accounting documents. A sender system is a system that generates cash flows from various source applications, such as accounts receivable, accounts payable, or bank statements. A Treasury workstation is a system that receives and processes cash flows from different sender systems and provides cash management and forecasting functions. You need to activate individual source applications on the sender system to enable the extraction and transfer of cash flows to the Treasury workstation. You also need to rebuild flow types in accounting documents on the sender system to ensure that the cash flows are classified correctly according to the Treasury workstation settings.