Is there a method to add a "file upload" shopper field? The main goal would be ask for a document during the checkout and if the cusomer uploads it we could download/receive it somehow.
This is not a per product custom field (like when you upload a photo for a T-shirt), this is a per order field because the customer sometimes need to confirm if he is allowed to receive the goods.
are you check standard joomla xml fields?
https://docs.joomla.org/Standard_form_field_types