If you have a class style already designed in you css put class name in a html code.
<i class="easypromoweb-icon-anchor"></i>
Like <i class="easypromoweb-icon-anchor classnameshadow"></i>
Or
https://css3gen.com/box-shadow/
#shadowid {
-webkit-box-shadow: 0px 5px 5px 0px rgba(50, 50, 50, 0.2);
-moz-box-shadow: 0px 5px 5px 0px rgba(50, 50, 50, 0.2);
box-shadow: 0px 5px 5px 0px rgba(50, 50, 50, 0.2);
}
<i class="easypromoweb-icon-anchor" id="shadowid"></i>
If you need help contact, let me know.
Sorry for my english.