Set up the Favicon Cart Count app
The Favicon Cart Count app works by displaying the number of items added to the cart over the browser's favicon, helping your store's browser tab stand out.
The app won't work if you haven't already added a favicon to your store. Check this 1-minute guide on adding a favicon to a Shopify theme.
You can customize the shape of the number's background, location, colors, and even add an animation - make it slide, fade or pop. The app currently works only on desktop browsers, such as Chrome, Firefox, and Opera.