Hi @manaptb,
Can you give some more details for you project and the current code for this block? Are you using fontawesome, or…?
With fontawesome you will have to work a little to get the size and colors right, but it will be a stacked icon, something like:
<span class="fa-stack fa-lg">
<i class="fas fa-circle fa-stack-2x"></i>
<i class="fas fa-envelope fa-stack-1x fa-inverse"></i>
</span>
Hope this helps,
Bob