...
If the Project Costing functionality is enabled in the application on the Administration > Settings > General Settings form Project Costing form, you can link a cash payment with a related project which you can select in the Project field (to find a project, start typing its name or code in the field).
The Planning Document field is available if the Use a payment calendar option is selected on the Administration > Settings > Cash Management Money form. The field is auto- populated in case when the payment is based on a Money Transfer (Plan) or Money Payment (Plan) document.
...