You can do that from the Themes section.
Head to: Online store > Themes > Actions > Edit Language
Now search for "Confirmed description" in the search box. You can find the edit option to change the Order confirmation status.
Alternatively, We can work with you to support Royal Mail Tracking using Shipment Tracking & Notify App if you are looking for an advanced customization in the "Order status" page. You can create a "Track your order" page as well, where your customers can track their order.
Thanks again Hari_K,
But this doesn't solve the problem. The message will not change from whatever you edit in here to 'order shipped' once it is shipped.
The 'order status' page will not show any updated 'order status' for orders shipped without tracking unless Shopify build some kind of way of manually updating the status for people who ship without tracking.
Hi @Feemish, I have just tested this and it has worked for me. With or without a tracking number, as soon as I mark it as fulfilled the order status page changes to my personal confirmation/delivery message.
Thanks... but I feel rather reluctant to have to pay $360 a year for an app to fix something that should work on Shopify already.
It's probably easier for people in the UK who ship without tracking to remove all links in their emails to the 'order status' page so their customer don't get confused by seeing the wrong information on it.... It looks like that's what other UK sellers are doing. Shame really.