On the Payment Details tab, you can provide information about pay period, department of the employee and linked documents. 
The "Cash Payment (create)" form. The Payment Details tab in single-row mode
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In the Department field, select the department whose employee are paid with the cash payment.
The Planning Document field is available if the Use a payment calendar option is selected on the Administration > Settings > Cash Management form.
If the Project Costing functionality is enabled in the application on the Administration > Settings > General Settings 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.
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There is a switch for changing the display mode which is located to the right on the tab, Table Mode. Use Table mode to apply the payment amount to multiple planning documents and projects. You can add documents one by one to the list in the table (refer to Table mode screenshot below). 
The "Cash Payment (create)" form. The Payment Details tab in table mode
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