You need to describe a typical transaction for a sale and a purchase. It is very irregular, if not unprecedented, to pay a commission to a customer. So who, exactly, pays what to who and for what?
umm… unless your agent or mediator accept credit (easy to track how much you owe them based on percentage or amount for comission payout) then create them as supplier first. if not just create the entry via bank transaction or cash transaction with their names inserted in payee section.
Note: you have to create the expenses account in chart of account via settings.
This is no more information than you provided initially. If you want help, you must furnish the information requested. For example, are your “customers” the end users? Are they sales representatives? Are they buying for themselves or for others? Describe a full transaction scenario.
In this case your “Customer” (given me order for sale) is also your “Supplier” (I pay Commission).
(1) Person A gives you an order for a product/service - $100, so they are a customer.
(2) Person A gets commission for that order - $10, so they are a supplier as they “supplied” you with the order.
So (1) would be a Sales Invoice for $100 and (2) would be a Purchase Invoice for $10.
This would be the reverse of the above. Person B as the supplier receives the order - $100 and Person B as the customer owes you the commission - $10.