In shopify admin panel ( settings > notifications > Email templates ) it allows you to edit the email sent to my distributor with order information on it like : address, price and the SKU to send that customer. I am trying to add the Barcode UPC to the email template as well.
This is the .liquid code for the SKU
(sku: {{ line.sku }})
Here is a link to the email variable reference guide but I cant find one for the barcode, any ideas?
http://docs.shopify.com/manual/settings/notifications/email-variables
You could store the upc in an unused product field (e.g. vendor) and then output this field in your email template {{ line.vendor }}.
If there are no unused fields available then you can store the upc in a metafield and output this metafield in your email template:
{{line.product.metafields.some_namespace.your_key}}
Here is the documentation for metafields: metafields
Where is the upc currently stored?