Theme has built-in FontAwesome icon so you can use icon font without uploading icon images. You can place FontAwesome icons on page/post content using <i> tag.
You can place Font Awesome icons just about anywhere using the CSS Prefix fa and the icon’s name. Font Awesome is designed to be used with inline elements (we like the <i> tag for brevity, but using a <span> is more semantically correct).
<i class="fa fa-camera-retro"></i>
Here are all listed icon which are available in FontAwesome. Please visit FontAwesome cheatsheet.