Hi,
HikaShop Business will give you an interface to directly edit the different parts of the email.
I added a patch in HikaMarket which will be available in the next release.
In the "preload" file, you will find in the "top" of the file the line
'vendor' => $data->vendor,
You have to replace it by
'vendor' => $data->vendor,
'customer' => @$data->customer,
Thanks to that patch, in the "html" file you will be able to use a tag
{VAR:customer.user_email}
To display the value of the field "user_email" of the HikaShop customer.
Regards,