You can use the QuickBooks mailing service to mail a single invoice from
Click Send at the top of the invoice and click Mail Invoice.
In the Send Invoice window, click Send Now.
If you want to e-mail this invoice, select Send by e-mail.
To check the status of a mailed invoice, go to the Customers menu,
choose Billing Solution, and then click Check Account Activity.
Mailing a batch of
invoices through QuickBooks (Billing Solution)
Mailing a sample invoice to
yourself (Billing Solution)