Just like the tailoring items, you can record the delivery of ready/retail items. If an order has both tailoring and retail items, then you can create a delivery record of them. Once both deliveries are recorded, the delivery status in the order window will show you that this order has been delivered.
To record the delivery of retail items, go to Sales then Orders, then edit the order and click on Misc. Actions
After you click Misc. Actions, you will see the option Deliver Retail Items, now click on Deliver Retail items
Then you can select the items, select delivery dates and add delivery notes (if you want to add any notes for any reference) then submit and the retail delivery will be recorded.