Keys in Keys.Discount are requested from Keys.Express shop and delivered from KD. The product SKU and order quantity is the determining factor on which key(s) are requested.
The delivery process is automatic for orders paid immediately (credit card) and if the key is in stock on KE.
Order with Paypal.me prepayment method #
this prepayment order is in status pending which means it has not been marked as paid yet.

If the order has been paid, you can just click the blue button Retrieve keys and Send Email.
it will automatically mark this order as paid (complete) and send out the keys.

Key is not in stock on KE #
If a key is not in stock on KE the system cannot send it. We need to add the key for this SKU in the Keys.Express shop and then come back to KD and click this blue button Retrieve keys and Send Email. to send the key out:
