Vanish Mode is a new chatting feature introduced in Facebook messenger, letting users send self-destructing or disappearing messages to one another.
You can send any content, which includes text, photos, video, and GIFs, through the Vanish Mode. These messages will disappear in the receiver chat once you turn off Vanish mode or leave the chat.
However, you can still access the messages you sent in Vanish Mode for the next 6 hours after you leave the chat. This is not possible if you turn off the Vanish Mode on Messenger.
I hope you learn what vanish Mode on Messenger is. It is like the disappearing messages on Snapchat. You can also use this in your Instagram Application; want to know how? Click here.
Check this article to learn How to block someone on Messenger.