Use Font Awesome Icons in CSS

Further to the answer from Diodeus above, you need the font-family: FontAwesome rule (assuming you have the @font-face rule for FontAwesome declared already in your CSS). Then it is a matter of knowing which CSS content value corresponds to which icon.

I have listed them all here: http://astronautweb.co/snippet/font-awesome/

Actually even font-awesome CSS has a similar strategy for setting their icon styles. If you want to get a quick hold of the icon code, check the non-minified font-awesome.css file and there they are....each font in its purity.

You can't use text as a background image, but you can use the :before or :after pseudo classes to place a text character where you want it, without having to add all kinds of messy extra mark-up.

Be sure to set position:relative on your actual text wrapper for the positioning to work.

.mytextwithicon {
    position:relative;
}    
.mytextwithicon:before {
    content: "\25AE";  /* this is your text. You can also use UTF-8 character codes as I do here */
    font-family: FontAwesome;
    left:-5px;
    position:absolute;
    top:0;
 }

EDIT:

Font Awesome v5 uses other font names than older versions:

• For FontAwesome v5, Free Version, use: font-family: "Font Awesome 5 Free"
• For FontAwesome v5, Pro Version, use: font-family: "Font Awesome 5 Pro"

Note that you should set the same font-weight property, too (seems to be 900).

Another way to find the font name is to right click on a sample font awesome icon on your page and get the font name (same way the utf-8 icon code can be found, but note that you can find it out on :before).