Now Provided, simple 'Font Awesome Icon'.
When Font Awesomr Icon use, plese refer 'Font Awesome css' from HTML file. example is
<link href="https://use.fontawesome.com/releases/v5.6.3/css/all.css" rel="stylesheet" integrity="sha384-UHRtZLI+pbxtHCWp1t77Bi1L4ZtiqrqD80Kn4Z8NTSRyMA2Fd33n5dQ8lWUE00s/" crossorigin="anonymous"/>