For handling the shipping process, there are different courier partners available that includes Sendle, Australia Post, FedEx, UPS, etc. You can handle the shipping process directly in Shopify using Sendle, which was recently introduced. All businesses with locations in Australia can now purchase discounted shipping labels from Sendle, directly through Shopify. You can look into more details here: https://www.shopify.com/blog/shopify-shipping-australia.
Alternatively, you can use an app like Multi Carrier Shipping Label that helps you integrate with carriers like Australia Post, FedEx, UPS and many more. The app allows you to display live shipping rates at checkout based on your orders, print shipping labels in bulk and also automate the tracking process by sending live tracking status emails to your customers.
Thank you so much for your advice!
One thing I am still not sure is whether they can offer warehouse function?
What I am thinking is source items from suppliers and stock at warehouse, and then
it will be dispatched upon order.
Or drop shipping is becoming more popular in Australia?
I would like to source items directly from supplier, without through wholesale.