I've got to add an EAV that I'd like to add to my "New Order" Email. How do I do that? I think my biggest problem is that I don't know what variables are available in the Email Templates. Sure, there's the popup that should tell me what I've got to work with, but then I look at the template and I see an order_data Variable that I can't see anywhere in the popup. So, any help on this is greatly appreciated.
Check this out, this might help : https://www.blog.sashas.org/magento-2-1-3-how-to-make-customer-attribute-update.html