Using Trackops, you can easily send invoices to your clients via email. You can even customize the Invoice Email template to include as much or as little detail as you'd like. It is also important to note that a printable PDF of the actual invoice is automatically attached to the outgoing email.
To send an invoice email, navigate to the invoice in question, and click Send > Send by Email.
If a client contact is associated with this invoice, their email address will automatically be populated into the window. You can optionally click the Change link to replace the email with a different address.
If the invoice is overdue, an option to include an Invoice Payment Reminder (overdue reminder) will also be available. This template can also be configured via the email template settings.