Favicons are small 16x16 icon files that are displayed next to the URL of your site in a browser's address bar. Additionally they're often displayed next to the name of your site in a user's list of open tabs and bookmark listings making it easier for the user to quickly identify amongst other sites.
After generating a favicon with this tool download and save to the root directory of your site. Then include the following code in the head of your HTML document.
<link rel="shortcut icon" href="/favicon.ico" type="image/x-icon"> <link rel="icon" href="/favicon.ico" type="image/x-icon">