font awesome v4.7 code example
Example 1: change font awesome icon size
<i class="fas fa-camera fa-xs"></i>
<i class="fas fa-camera fa-sm"></i>
<i class="fas fa-camera fa-lg"></i>
<i class="fas fa-camera fa-2x"></i>
<i class="fas fa-camera fa-3x"></i>
<i class="fas fa-camera fa-5x"></i>
<i class="fas fa-camera fa-7x"></i>
<i class="fas fa-camera fa-10x"></i>
Example 2: cannot use font awesome in php mvc
<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.2.0/css/font-awesome.min.css" rel="stylesheet">