MailAddressFieldName Property
Returns or sets the name of the field that contains e-mail addresses that are used when the mail merge destination is electronic mail. Read/write String.
expression.MailAddressFieldName
expression Required. An expression that returns a MailMerge object.
Example
This example merges the document named "FormLetter.doc" with its attached data document and sends the results to the e-mail addresses stored in the Email merge field.
With Documents("FormLetter.doc").MailMerge
.MailAddressFieldName = "Email"
.MailSubject = "Amazing offer"
.Destination = wdSendToEmail
.Execute
End With