Direct mails are physical post emails which you will be sending in an envelope using a third party vendor. Maybe I'm not seeing the full picture but attachment in this scenario doesn't look to be a good idea.
My goal was to create a new template for Direct Mail. When one uses the Bulk Delivery option, campaign provides you ability to add a .odt file to the delivery and process the personalization rule in that file (Trying to apply the concept of Attachments in the direct mail delivery).
Hence, I asked what's the purpose of "account"?
But, as i understand from your comment, we are not suppose to use that "Bulk" delivery option for Direct Mail channel. Is this assumption correct?
Direct mails are physical post emails which you will be sending in an envelope using a third party vendor. Maybe I'm not seeing the full picture but attachment in this scenario doesn't look to be a good idea.