Messages sent using the Vanish Mode feature in Messenger can be automatically deleted. That is, the message will be deleted after a certain time as soon as you see the recipient. However, for this, you must turn on the vanish mode before sending the message.
To activate the vanish mode, you need to tap on the profile picture of the person you want to exchange messages with by launching the Messenger app on your mobile phone. Now on a new page, you can see different options to control the conversation. From the options, select the Vanish mode under the Privacy section or tap Ok to see the Vanish mode screen. Messages written on the screen will be automatically deleted after viewing the recipient. Group chat, video, and audio calls cannot be made using Vanish mode.