font awesome

1<link
2      rel="stylesheet"
3      href="https://use.fontawesome.com/releases/v5.13.0/css/all.css"
4      integrity="sha384-Bfad6CLCknfcloXFOyFnlgtENryhrpZCe29RTifKEixXQZ38WheV+i/6YWSzkz3V"
5      crossorigin="anonymous"
6    />

1<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.15.1/css/all.css" integrity="sha384-vp86vTRFVJgpjF9jiIGPEEqYqlDwgyBgEF109VFjmqGmIY/Y4HV4d3Gp2irVfcrp" crossorigin="anonymous">

1<link rel="stylesheet" href="path/to/bootstrap/css/bootstrap.min.css">
2<link rel="stylesheet" href="path/to/font-awesome/css/font-awesome.min.css">
3
4<script src="https://kit.fontawesome.com/8aec3381bb.js" crossorigin="anonymous"></script>

1  <link
2  rel="stylesheet"
3  href="https://use.fontawesome.com/releases/v5.7.2/css/all.css"
4  integrity="sha384-fnmOCqbTlWIlj8LyTjo7mOUStjsKC4pOpQbqyi7RrhN7udi9RwhKkMHpvLbHG9Sr"
5  crossorigin="anonymous"
6/>

1Font Awesome is a font and icon toolkit based on CSS and Less.
2
3It was made by Dave Gandy for use with Bootstrap, and later was incorporated
4into the BootstrapCDN.
5
6Font Awesome has a 38% market share among those websites that use third-party
7font scripts on their platform, ranking it second place after Google Fonts.

1add_action( 'wp_enqueue_scripts', 'tthq_add_custom_fa_css' );
2
3function tthq_add_custom_fa_css() {
4wp_enqueue_style( 'custom-fa', 'https://use.fontawesome.com/releases/v5.0.6/css/all.css' );
5}