1. Lock the Entire WhatsApp App

You can lock the entire WhatsApp application using the built-in fingerprint or Face ID lock:

For Android:

1. Open WhatsApp.
2. Tap the three dots in the top right corner to open the menu.
3. Go to Settings>Account>Privacy.
4. Scroll down and tap the Fingerprint lock.
5. Turn on Unlock with fingerprint and follow the prompts to set it up.

For iPhone:

1. Open WhatsApp.
2. Tap Settings in the bottom right corner.
3. Go to Account>Privacy.
4. Tap Screen Lock.
5. Enable Require Face ID or Require Touch ID and set the desired time interval.

2. Use Third-Party Apps (for Android)

If you want to lock specific chats, you can use third-party apps that offer app-locking features. Here’s how:

1. Download an App Lock from the Google Play Store (e.g., AppLock, Norton App Lock, etc.).
2. Open the App Lock app and set it up, following the on-screen instructions to create a password or pattern.
3. In the App Lock app, find and lock WhatsApp and other apps you want to secure.
4. Some App Lock apps also offer the ability to lock specific chat windows within WhatsApp.

3. Archive and Mute Chats

Another method to make specific chats less accessible is to archive and mute them:

Archive a Chat:

• Long press on the chat you want to hide.
• Tap the Archive icon (a box with a downward arrow).
• The chat will move to the archived section and be less visible on your main chat list.

Mute Notifications:

• Open the chat you want to mute.
• Tap the contact name at the top.
• Tap Mute notifications and select the duration.

While these methods do not lock the chats directly, they do add an extra layer of privacy by making them less noticeable.

Summary

• For entire app security: Use WhatsApp’s built-in fingerprint or Face ID lock.
• For locking specific chats: Use third-party app lockers for Android.
• For hiding and muting chats: Archive and mute notifications.

Each method provides a different level of security and convenience, depending on your needs.