Yes, it is possible to use simple HTML formatting in the email content, such as:

• <b>Bold text</b>
• <strong>Important text</strong>
• <i>Italic text</i>
• <em>Emphasized text</em>
• <mark>Marked text</mark>
• <small>Smaller text</small>
• <del>Deleted text</del>
• <ins>Underlined text</ins>
• _{Subscript text}
• ^{Superscript text}

For more information, see this website: https://www.w3schools.com/html/html_formatting.asp

Please note that it is only possible to apply the HTML formatting to the email content, not to the email subject.

It is not possible to include signatures or images in an email (this feature is coming soon).