Screenshots
Click on Client Payments and then CCCF
Select the line that has been paid direct to the supplier and select the payee:
If they have only paid a deposit (ie cruise or tour) then you can toggle Partial Payment so that you can adjust the amount they paid.
Add notes in the Comments (will appear on receipt) or Auth (will appear in VTO supplier payments tab)
Then click Create New
You will then get a receipt that you can sent to the client

Both the client & supplier payments are automatically receipted:
If you enter the wrong amount, you can click on the red X in the Client Payments tab to cancel and re-receipt: