It's not possible to send HTML emails using just the Amazon SNS. Instead, you can use Amazon SES to send the emails and SNS to trigger the sending process.
So, if you have an endpoint which takes care of sending email through Amazon SNS. You can create a topic, subscribe to the endpoint to receive notifications. This notification will trigger the mail.
You can setup endpoint to take parameters from the JSON data stored in the notification and send the email using that information.