Fingerprint lock feature can be activated in such a way in WhatsApp...

Messaging app WhatsApp now features biometric authentication for Android and iPhone users. Although this feature was already announced for iOS users, this feature is now being made available through the Beta update for Android users.

Apart from the fingerprint scanner for Apple, Face ID support is provided. Since Apple introduced Face ID with the iPhone X, this new Apple iPhone now has the support of Face ID. If you use an Android smartphone, here's a way for you to activate the fingerprint scanner. This feature is in WhatsApp beta version 2.19.3, so your app needs to be updated.
Then open WhatsApp and go to Settings here. Tap on Account and select Privacy here. Scroll down and here you see the Fingerprint lock option. When selecting Fingerprint lock WhatsApp will give you the notification to touch the fingerprint sensor. Now on WhatsApp this option will get what you want to keep the phone lock durations. From here, you will get the option of one minute to 30 minutes. There is a way for iOS users to set up a Face ID in WhatsApp. Open WhatsApp. Tap on the account. Select the Privacy option here. Select the screen lock below you. At the top you'll get the Require Face ID if your iPhone has Face ID support.