How can I send Newsletter in HTML format? I have  installed the following modules simplenews, mailsystem, html mail to send HTML news letter from a Drupal 7 site. Right now, I am just able to send plain text email from send test option. How can I send an HTML email from my site? How can I send a newsletter to registered emails of my site?
You can use Mime mail along with your newsletter module to enable HTML in your emails. This module will work on the message mime so it should work with almost any mail module