Favicon is a little icon that browsers display on a browser tab, or in the address bar next to its URL. It also is used when you bookmark a page.
Create an image which you want to use as logo as well as favicon. Save the file as favicon.ico. Usually the size of favicon is of 16×16 pixels.
To insert favicon place this line of code in the head tag of your html
<link rel=”shortcut icon” type=”image/x-icon” href=”favicon.ico” />