WhatsApps is already secured from a communication side of things due to end-to-end encryption being enabled by default. What it doesn’t enable by default is the privacy lock. This means if someone was to use your phone, they could easily read your messages.
If the phone is stolen and they manage to bypass the login screen, they could read your conversation history and find something interesting. You could send a ‘remote wipe’ but the thief could just keep the device offline.
This is why it’s important to enable such features across all your applications. For now, let’s focus on WhatsApp.
Go to Settings > Account…
Click on Privacy and click Fingerprint Lock at the bottom…
You will then be asked to Confirm your fingerprint
Once done, you will be able to set a timeout..
and you are done… After your chosen time, the application will lock itself and require your fingerprint before you can access your messages.
If you don’t see the option, you will need to update WhatsApp.