How to setup contacts so that the print commercial documents sends email to the customer contact?

Summary:

How to setup Contacts so that the print commercial documents job sends email to the customer contact?

Content (please ensure you mask any confidential information):

We want to have the "Print Commercial Documents" job automatically send the invoice through e-mail to the Customer contact. And also have the customer statements work.

But we are having trouble setting this up, cause all setup we did seems to not have the correct response and the e-mails are not being sent.

What setup steps do we need to do for this features to work?

Regards,

Joana

Version (include the version you are using, if applicable):