These are free favicons that you are free to use on your website with no credit required to link back. To add a custom favicon to your website, save the favicon to your computer and upload it to your website. You will then need to edit your website and insert
<link rel="Shortcut Icon" href="YOURWEBSITE/favicon.ico" /> replacing YOURWEBSITE with your actual website address.
If you would like to view more favicons that I have created, you can view my DeviantArt gallery. I hope you enjoy these and if you have any suggestions for a set that you would like to see, you are welcome to contact me.