how can I edit the text of order confirmation emails?
There a couple of ways to edit the email confirmation depending on what you want to accomplish. Currently you cannot fully edit the email (although that function is coming). You can edit the first line and last line in Layout/Email Layout. You can additionally add an Order Confirmation Email Addendum either site wide for every order by going to Settings/Policies, Addendum, and Disclaimers/Order Confirmation Email or you can add the addendum to a specific product by edit/next/Email Addendum.