I use fontawesome to show icons in my project
For example I use these tags in some place
<link href="https://use.fontawesome.com/releases/v5.8.1/css/all.css" rel="stylesheet" />
<i class="fas fa-map"></i>
<i class="fas fa-map-marked-alt"></i>
The first one is being shown but the second one isn't. Consider that both of icons are free icons