Go to your iPhone's home screen. Touch and hold the background of your home screen until the app icons jiggle. A screenshot ...

This icon means that your iPhone's Do Not Disturb feature is enabled ... It should be noted that you might also see the half-moon icon in your Messages app. This means that alerts are muted ...

Open the Messages app from your iPhone's homescreen ... For example, if you select the heart icon, the text's sender will receive a notification that says "Meira loved '[insert message here].'" ...