Check out example codes for "font-awesome cdn". It will help you in understanding the concepts better.
Code Example 1
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" integrity="sha384-wvfXpqpZZVQGK6TAh5PVlGOfQNHSoD2xbE+QkPxCAFlNEevoEH3Sl0sibVcOQVnN" crossorigin="anonymous">
Code Example 2
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" crossorigin="anonymous">
Code Example 3
<link rel="stylesheet" href="path/to/font-awesome/css/font-awesome.min.css">
Code Example 4
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
Code Example 5
<script src="https://kit.fontawesome.com/8ef165f656.js" crossorigin="anonymous"></script>
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