If you have an iPhone 12, there are a few ways to show an alarm icon on the lock screen. You can use the Settings app to change the alarm preferences, or you can use the Alarm app. The Alarm app is a free app that you can download from the App Store. The Alarm app has a few options when it comes to showing an alarm icon on the lock screen. You can choose to show an alarm icon in a small window, or you can show it in full view. You can also choose whether or not to sound an alarm when the icon is shown on the lock screen. If you choose to sound an alarm, you will need to set up a sound preference in the Settings app. The Alarm app also has a settings option for how long after each alarm sound is played. If you have any questions about how to show an alarm icon on your iPhone 12, please feel free to reach out to us at support@apple.com and we will be happy to help!