add font awesome icons css code example
Example 1: add icon font awesome
<i class="fa fa-plus" aria-hidden="true"></i>
Example 2: adding font awesome to css
<link rel="stylesheet" href="path/to/font-awesome/css/font-awesome.min.css">
<i class="fa fa-plus" aria-hidden="true"></i>
<link rel="stylesheet" href="path/to/font-awesome/css/font-awesome.min.css">