Microsoft Office Outlook formats outgoing email in HTML mode, which allows you to include active, clickable links in mail messages. Outlook also offers plain text and rich text as email formatting ...

Message Formatting in Thunderbird. With a dash of creativity and Mozilla's Thunderbird desktop email program, you can compose professional looking business emails that should impress your recipients.

A new app, MarkdownMail, lets you send HTML-formatted e-mail from your iOS device, via the Markdown formatting language.