This is an accepted solution.
Hyde here from Shopify.
You could edit that wording by using the Language Editor. There's more information on that feature here.
You go to Online Store > Themes > Actions > Edit Languages and you'll come to a page like this:
If you go to Checkout & System and scroll all the way down to Page Titles you'll see the field you need to edit:
Simple change the wording and remember to hit "Save" in the top right.
I hope this helps!
All the best, Hyde.