In the current process of order picking, once the order has been picked confirm, then the 'Ready to ship' status update gets triggered to Marketplace, which the marketplace integrated courier gets the order pickup update, and courier will then go to the warehouse to collect the order. Another possibility is that courier goes to the warehouse at stipulated time for daily collection of orders as per pre-arranged between you and the courier.
We hope the details above were helpful for you. Please feel free to share with us if require further assistance and will be happy to take it up.