Apps can display a small red oval containing a white number on their app icon to indicate when new and important information is available.
Make badging intuitive. People should know why your app icon is badged and how to find the related information when they open your app.
Minimize badging. Don’t overwhelm users by connecting badging with a huge amount of information that changes frequently. Use it to present brief, essential information and atypical content changes that are highly likely to be of interest.
Draw attention to important information inside your app too. If you rely solely on app icon badging to highlight information, you run the risk of people missing it. Displaying badges on a tab bar or elsewhere within your app is another way to direct users to important content.
Avoid supplementing badging with alerts. Even when new or important information is available, users don't want to see an alert the moment they open your app. Instead, make the information discoverable. For related design guidance, see Error Handling and Alerts.
Keep badges up to date. Update your app’s badge as soon as the corresponding information is viewed. You don’t want people to think new or important information is available, only to find that they’ve already seen it.