Summarize your app for prospective users
Your app’s subtitle is intended to summarize your app in a concise phrase. Consider using this, rather than your app’s name, to explain the value of your app in greater detail. Avoid generic descriptions such as the “world’s best app.” Instead, highlight features or typical uses of your app that resonate with your audience. You can update your subtitle when submitting a new version of your app to help you determine the subtitle that’s most effective for engaging users. A subtitle can be up to 30 characters long and appears below your app’s name throughout the App Store.