The end-to-end message encryption Facebook promised to Messenger users back in July has finally finished rolling out to everyone. Here’s how to enable it.
A source at Facebook informed Wired that its new “Secret Conversations” functionality is now available to all 900 million users of the service. The new end-to-end encryption doesn’t turn on automatically, however. You have to turn it on for each conversation.
If you want to start a new encrypted conversation:

1. Tap the new conversation icon at the top right.
2. Tap “Secret” in the top right.
3. Choose your recipient and begin messaging.

If you want to turn an ongoing conversation into an encrypted Secret Conversation:

1. Open the message thread.
2. Tap their name at the top of your screen.
3. Tap “Secret Conversation” to switch it over.

If you don’t see those options, it could mean the recipient doesn’t have the current version of Facebook Messenger. They’ll need to update their app for Secret Conversations to work. Also, Secret Conversations don’t allow the sending of GIFs and videos, but you can still share picture and use stickers. And it’s important to note that you can only access your Secret Conversations from the device it was enabled on. So if you start an encrypted conversation on your phone, that’s the only place you can send and receive encrypted messages for that particular conversation.