Hello Swapnesh,
There are several useful threads on DevNet on this topic already:
- http://devnet.kentico.com/questions/how-to-change-favicon-image
- http://devnet.kentico.com/questions/how-to-change-favicon-image-1
- http://devnet.kentico.com/questions/replacing-default-favicon
These should apply for versions 9 and older. In Kentico 10 we improved the support for custom favicons, please check our documentation here:
https://docs.kentico.com/k10/configuring-kentico/managing-sites/setting-a-site-favicon