Font Awesome Icons as squares [closed]

You should be using Font Awesome’s provided <link> or <script> tag(s) that they give you with your kit. It should look like this:

<link rel="stylesheet" href="https://kit.fontawesome.com/xxxxx.css" crossorigin="anonymous">

or if you prefer the JS method:

<script src="https://kit.fontawesome.com/xxxxxxx.js" crossorigin="anonymous"></script>

Copying and pasting the code from their CSS file to your local one isn’t advisable because there are relative links to Font Awesome custom fonts that can’t/won’t be included in your site’s files. (As @Alexander Holsgrove points out)