Facebook: Enable end-to-end encryption on Messenger, here's how

Despite Facebook Messenger's assertions to the contrary, regular chats held through the app are not end-to-end encrypted, putting your sensitive information in great danger. 

End-to-end encryption makes sure that no one in the middle, not even Meta/Facebook, can access the content you send and assures that only you and the recipient can read or listen to what is delivered. 

Unfortunately, unlike WhatsApp, end-to-end encryption is not turned on by default, thus it is your responsibility to do so in order to prevent other parties from listening in on your conversations. On the bright side, turning it on is simple once you know how; however, it can only be done for specific contacts; it cannot be changed globally. It takes engaging in a "Secret conversation" before beginning an encrypted communication with someone. The procedures are demonstrated in the steps below. 

Step 1. To speak with someone using end-to-end encryption, open the Messenger app and tap their profile icon. 

Step 2. Tap their profile icon once more at the top of the conversation window. 

Step 3. Click the Go to secret conversation button under "More Actions." 

You are now in a discussion window with end-to-end encryption enabled. From this point, you may also choose to have all of your messages completely removed from the discussion thread on both your device and the device of the person with whom you are conversing.

Tap the clock banner at the top of the discussion window to accomplish this. Alternatively, you can pick Disappearing messages and set an expiration period by tapping the top-left profile of the person you'll be conversing with.