在php代码中添加一个字体真棒图标

I'm using WordPress CMS to develop my website. I need to put a font awesome icon before a heading. See below snapshot for placement.

This is the current php code:

if(empty($search_label)) {
$search_label = 'Search Inventory';}

I'm a beginner to PHP so, I appreciate if anyone has a solution to do this easily.

Thank you!

First of all, include font awesome CSS file in the header.

and then

if(empty($search_label)) {
$search_label = '<i class="fa fa-search"></i>Search Inventory';}