For the system to allow you to create a credit there must be a monetary difference. The ability to create a return only appears after the delivery being confirmed including the products that you intend to send back to your supplier.
Credits
The invoice has failed the 3-way check and the difference is from the purchase order tab
The delivery tab has been receipted incorrectly and matches the invoice tab, click the unlock delivery button to correct and redeliver. Please review our guide on unlocking deliveries.
The value of the credit is lower than overall cost of the invoice, in these circumstances you can raise a credit from the dashboard, to learn more please view our guide on creating credits.
The ability to create credits is switched off in the user's role.
The ability to create credits is switched off in the supplier's order management settings.
The user is not attached to the mini market and site the order was placed through.
Returns
The ability to returns is switched off in the user's role.
The ability to returns is switched off in the supplier's order management settings.
The user is not attached to the mini market and site the order was placed through.
The delivery has not been receipted.