add font awesome to your website using cdn code example
Example 1: font awesome cdn
<script src="https://kit.fontawesome.com/a9545f17e8.js" crossorigin="anonymous"></script>
Example 2: font awesome cdn
<link rel="stylesheet" type="text/css" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.4.0/css/font-awesome.min.css">