To email a summary of unpaid invoices:
Open either the Unpaid Invoices or Overdue Invoices report, both available under the Customers and Reports menus.
Under each customer section, there are options to email or print a balance statement or payment reminder with the list of invoices due for the customer.
For the email option, the recipient and sender emails are prepopulated with the information on customer and account records but can still be edited before sending:
