WhatsApp Chat Lock
You can secure a conversation by locking it, moving it to a separate folder that demands a password or biometric authentication, like a fingerprint, to open.
When you lock a conversation, the app will also hide its contents from alerts. To secure a conversation, simply tap the conversation’s name and choose the lock option. These conversations are hidden until the user enters their phone’s passcode or biometric.
WhatsApp said in their announcement “We think this feature will be great for people who have reason to share their phones from time to time with a family member or those moments where someone else is holding your phone at the exact moment an extra special chat arrives.”.
The upgrade arrives after WhatsApp introduced a few new features related to polling and sharing a few weeks ago. One of the new features allows you to conduct polls in which each participant is only permitted to cast a vote once. When sending media along, you can now include captions.