lms/community/templates/emails/mentor_request_creation_email.html

<div>
  <p>Dear {{ member_name }},</p>
  <br>
  <p>You've applied to become a mentor for this course. Your request is currently under review.</p>
  <p>If you are not any more interested to mentor the course {{ course }}, you can <a href="{{ course_url }}">cancel your application</a>.</p>
  <br>
  <p>Thanks and Regards,</p>
  <p>Team Community.</p>
</div>