On the Payment Details tab, you can provide information about documents associated with the cheque issued, taxation details, and information about the exchange rates used for the document. 
The "Cheque Issued (create)" form. The Payment Details tab in Single-Row mode
There is a switch for changing the display mode which is located to the right on the tab. There are the following two options:
- Single-Row Mode. By default, this option is applied. Use this mode if the cheque issued is applied only to a single document.
- Table Mode. Use this mode to apply the cheque amount to multiple documents. Use the Add button to add documents one by one. Refer to the screenshot below.
...
In the Document field, select a customer document that will be paid with this payment.
In the Order field, specify a customer order to which this cheque is related.
In the Proforma Invoice field, specify an invoice related to the cheque issued.
The Planning Document field is available if the Use a payment calendar option is selected on the Administration > Settings > Cash Management form. The field is auto- populated in case when the payment is based on a Money Transfer (Plan) or Money Payment (Plan) document.
If the Project Costing functionality is enabled in the application on the Administration > Settings > General Settings form, you can link this cheque issued 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).
Table mode
To add a document, click the Add button on the table toolbar. As you add documents, the columns are populated. 
The "Cheque Issued (create)" form. The Payment Details tab in Table mode
...
If the cheque amount was applied to multiple planning documents and projects, make sure that the sum in the Payment Amount column is equal to the cheque amount in the Total field below the table.