Manipulate Email Notification to Arrive in Plain HTML

In order to ensure a missed call or voicemail is addressed, I have established select profiles to send email notifications to our Jira Project using their built-in email handler. This auto-generates a ticket for my team to receive and action the ticket. While the current transfer of data satisfies the requirement, if I could convert the email notification into plain HTML it would/should remove the banner data that is transferred over. We can gladly clean this text up by simply editing the notification box, but this enhancement would help.