Favicon is a small icon that appears at the top of a web browser.
Here are examples of favicons: Google, Yahoo, AOL, YouTube, Bitrix24.
How to set the website's favicon
Go to the Sites section > select a website > click Actions > Configure site.
Click More > Favicon.
Click edit > select the image (the image size: 16х16, 32х32, 48х48). Save settings.
Publish the website again, and the new favicon will appear.