If you need to put your website logo in the top address bar instead of browser's logo then follow these steps.
1. Add a file called "favicon.ico" (an icon file of your website logo) to your website root directory.
2.Insert the following HTML tag inside the <head> ... </head> section of your web page.
<link rel="shortcut icon" href="favicon.ico" >
**If you are working with master pages then put this code in head section of master page otherwise you have to put this code in every page.