What is the difference between sending email messages in TEXT mode or in HTML?
Answer: Email can be sent as either plain text or formatted in HTML. So what exactly does that mean? Well, originally, email was based on just straight text. What you typed was what you saw. With the new HTML-formatted emails, you can include pictures, hyperlinks, and other web page characteristics in your emails. It's almost like composing a web page within an email message. Unfortunately, if the person you are sending an HTML-formatted message to is using an email program that doesn't support HTML, they'll get a message with a lot of HTML tags (<BODY>, <HTML>, etc.) and HTML codes, such as scattered throughout the text. The good news is that most email programs default to the plain text format as long as you don't include any pictures, or other HTML elements.
To check your email program's settings, check the Options or Preferences and look for the "Formatting" section. This should tell you how your outgoing messages are being formatted. If there is no such option, you can be pretty sure that you're only sending plain text messages.