The Invoice Mail Merge Template is where the invoice cover letters are stored. These letter templates differ from the invoice that is generated from the Online Payment Page. The letter templates are created in the Word style editor. 

While the Mail Merge Invoice Template letter contains many of the same merge fields as the invoice, it also contains the merge field for the unique URL to pay the invoice with a credit card.

The invoice and the cover letter can be sent together using the individual mail merge or Print/Email Mail Merge feature under the Actions menu on the main Invoice Grid. Be sure to filter the grid to include only Unpaid or Partially Paid invoices under the Status column.

You can choose to create just the Mail Merge Template and do not select an attachment. Or, choose the attachment and select Skip Page 1 under Format. This will produce just the invoice, not the cover letter. A Mail Merge Template must always be chosen, regardless of whether it is printed or not. Complete the rest of the fields and click "OK" to complete.