MyPost Business Fulfillment Service
Australia Post Shipping imports your customer orders from Shopify to your MyPost Business account, allowing you to easily print labels and manage your fulfillments.
MyPost Business is an account with Australia Post which allows businesses to manage fulfillments, print labels, save on shipping costs, and also pay for shipping online.
If you haven't already opened your MyPost Business account you'll need to do that first (it's free of charge). Find out everything you need to know at the Australia Post MyPost Business page.