A mail to html

You want to convert a plain text email to HTML format. Here's a basic example of how you can do it:

Plain Text Email:

Subject: Hello World!

Dear John,

This is a test email. It's just a simple message to see how it looks.

Best regards,
Jane

HTML Email:

<html>
  <head>
    <meta charset="UTF-8">
    <title>Hello World!</title>
  </head>
  <body>
    <h1>Hello World!</h1>
    <p>Dear John,</p>
    <p>This is a test email. It's just a simple message to see how it looks.</p>
    <p>Best regards,</p>
    <p>Jane</p>
  </body>
</html>

Here's a breakdown of what changed:

Note that this is a very basic example, and you can add more formatting and styling to your HTML email using CSS and other HTML elements. Additionally, you may want to consider using a templating engine or a dedicated email marketing platform to create and send HTML emails.