Once you fulfil an order in your Shopify admin, Shopify automatically notifies Zopa that the order has been fulfilled. This acts as the trigger for Zopa to release payment to your account.
You do not need to complete any additional steps in the Zopa Merchant Portal, and there is no required timeframe for fulfilling an order.
Exception: If you have agreed to receive payments through Autopay as part of your go-live agreement with Zopa (arranged with your Sales Agent), your payment trigger and disbursement timing may differ from the standard process described above.
For more information on payments, see here.