HTML
<a href="#" class="btn btn-secondary btn-lg btn-demo" role="button"><i class="fa-solid fa-house-chimney"></i></a>
Font Awesome CSS
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.2/css/all.min.css">
CSS (demo on this page)
.btn-demo {
width: 40px;
height: 40px;
font-size: 1em;
border-radius: 100%;
padding: 8px;
text-align: center;
border: 1px solid #ffffff;
outline: 1px solid rgba(255, 255, 255, 0.60);
outline-offset: 4px;
}