Swati,
You would do this in a custom HTML block. Here is an exapmle:
<style type ="text/css">a {text-decoration: none}</style>
<p><a href="http://www.leadmd.com" style="text-decoration: none">Link Here</a></p>
This will only display the "Link Here" with no underline. You can add additional modifications as well.
-Rodney
LeadMD