Using Font Awesome
Font Awesome is a toolkit on the CKEditor that lets you add icons to your web page. But these aren't ordinary icons. The icons are created using fonts, so unlike images, these icons can be resized without losing quality, just by adjusting the font size of the icon itself. Font Awesome is one of several libraries of icons and more will be added in the future.
To use a Font Awesome Icon, navigate to the node you'd like to work on (like a modular page or basic page) and edit that node. Then scroll to CKEditor and choose the icon that looks like a black flag. You'll know you have the right one when you hover over the icon and it says "CKAwesome".
From the popup menu, select the icon you wish to insert.
You can also use the search box to find an icon.
Next, select your size and then click, "Ok".
Be sure to save your work to see the results.