Use Bootstrap Glyphicon for icons in text, buttons, toolbars, navigation, or forms

We can use Bootstrap Glyphicon for icons in  text, buttons, toolbars, navigation, or forms :
as long as we have Bootstrap library

Example, comment icon


<span class='glyphicon glyphicon-comment'></span>

And more examples

<p>Envelope icon: <span class="glyphicon glyphicon-envelope"></span></p>
<p>Search icon: <span class="glyphicon glyphicon-search"></span></p>
<p>Print icon: <span class="glyphicon glyphicon-print"></span></p>

 

Reference:

 http://www.w3schools.com/bootstrap/bootstrap_ref_comp_glyphs.asp