#1. First, you need to find the ID of the Text Block.
In my example, we will have:
- #block-yui_3_17_2_1_1723019960346_3692

#2. Use this code to Code Injection Header (If your plan is Personal Plan, you can add it via Code Block in the Site Footer)
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.1.1/css/all.min.css" integrity="sha512-KfkfwYDsLkIlwQp6LFnl8zNdLGxu9YAA1QvwINks4PhcElQSvqcyVLLD9aMhXd13uQjoXtEKNosOWaZqXgel0g==" crossorigin="anonymous" referrerpolicy="no-referrer" />

#3. Use this code to Custom CSS box
#block-yui_3_17_2_1_1723019960346_3692 p:before {
content: "\f04b";
font-family: "Font Awesome 6 Free";
font-weight: bold;
color: #f86443;
font-size: 30px;
margin-right: 5px;
}

#4. Result
