How do I set my message to
disappear in a Messenger end-to-end encrypted conversation?
How to Enable Disappearing Messages in Facebook Messenger
You can set a timer to have everyone's messages
disappear from an end-to-end encrypted chat at a time that you choose after
they've been seen.
Anyone in the end-to-end encrypted conversation can
reset the timer. If you send a message to someone and they don't read it within
14 days, the message will automatically disappear from the conversation.
To choose when your messages
disappear from your conversation:
From Chats, tap on the secret conversation.
At the top of your chat, tap the person's name or
the group chat name.
Tap Disappearing messages.
Select when you want messages to disappear from the
chat after they've been seen.
Note: Remember that you or someone else in your end-to-end encrypted
conversation can report the conversation with a message timer for up to six
hours after the message has disappeared. Bear in mind that you only use
disappearing messages with people that you trust.
For example, it's possible for someone to:
Forward or take a screenshot of a disappearing
message and save it before it disappears.
Copy and save content from the disappearing message
before it disappears.
Take a photo of a disappearing message with a
camera or other device before it disappears.
If we detect that someone took a screenshot or a
screen recording of your end-to-end encrypted conversation, you and the people
in the conversation will be notified.
Bear in mind that we may not be able to detect all
screen recordings or screenshots, and you must update your
Messenger app to the latest version to get this experience.
Source:facebook.com/help