What is a favicon? A favicon is the small 16 x 16 icon you see in the that appears in a browser tab just to the left of the page title.
Favicons are used to represent saved pages in your favorites or bookmarks. They are used on the left side of your browser’s address bar for active pages. They are used in lists of predictive web addresses. Most importantly, they are used to mark open tabs in your browser.
What is an Apple touch icon? An Apple touch icon is seen on mobile devices like an iPhone or iPad. The Apple touch icon appears as soon as you bookmark a web site or add it to your home screen. It is the only element still visible once you leave the site.
Having a custom favicon and Apple touch icon shows that you pay attention to the details of your website, makes it easier for your customers to find your tab in a sea of open browser tabs, sets you apart from your competition, and aids in the branding of your site.