I have created a free module which lets you edit email templates and override them in the module. You can revert to Prestashop defaults just by disabling or uninstalling the module. There is no class overrides here. All safe.🙂
You can download from here. This module adds delivery and invoice address to the email templates.
I need you to tell me what email theme are you using right now and which template file do you need to be edited?