Hi @alex120ft, This should certainly be possible. As you can see at the bottom of this page here: https://www.playtimepottery.net/api-test?hs_preview=QJXutdaU-6152997013, I've included a font awesome icon using an
:after pseudo selector in that red CTA. Here's an image of my CSS: http://prntscr.com/l2a9lh.
You can also put the code in your stylesheet if you'd prefer. Since the CTA's page doesn't have the font awesome library loaded in, we just see a square, but see the correct icon on a live page since the Font Awesome reference has been loaded into the stylesheet I'm using on that page.
If you give me the CTA in particular that you're having trouble with, and the page you're trying to place it on I can certainly look into more detail for the specific issues you're having.