We use Font Awesome to handle icons across the site. We have a Pro licence which is integrated directly into the theme, meaning all FA icons can be called directly in a page layout by adding an html block and typing the FA code, which can be found against the icon in the Font Awesome directory.
For example, by adding an html block and typing:
<i class="fa-solid fa-thumbs-up"></i>When you view the page you will see:
Since we have a pro licence, we can also add our own custom icons to the site, which have been designed in-house. A guide to all those icons and their useage can be found here.