Adagio applications have 'Email Cover Sheets' that are part of the emailed documents. This supplies not only the Subject line of the email but also the text of the email. You may insert database fields (customer name, invoice amount, due date, etc) into the Email Cover Sheet - the text but not the subject. The actual invoice is a PDF attachment to the email.

An email address can be entered directly on the invoice, different than what is on the customer record. In the case of OrderEntry, there are 2 different email addresses yo can add (one for the bill-to and another for the ship-to). When emailing, you choose which email address to use (either the bill-to, the ship-to or the one on the customer record).

If you chose to download an evaluation of the Adagio programs and look at the supplied sample data, there are examples of the email cover sheets that can be set up.