Write an article based on this "Open Facebook Messenger on your iPhone or iPad. Tap the person you want to message. Type your message and tap the Send button. Check the message status."
It’s the blue and white chat bubble icon with a sideways lightning bolt inside. You’ll usually find it on the home screen. Messenger is set up to automatically show you when someone has read your message. This opens a conversation with that person. It’s the blue paper airplane icon at the bottom-right corner of the message. A blue check mark in a white circle means you’ve sent the message, but the person has not yet opened Messenger. A white check mark in a blue circle means the person has opened Messenger since you’ve sent the message, but they haven’t read it. When the person’s profile picture appears in a tiny circle below the message, you’ll know the message has been read.