WhatsApp with over 1.2 billion users has started to roll out a 2-step verification to provide additional security to user accounts.
One needs to have the latest WhatsApp update to enable this feature. Once you receive the update, activate this feature by opening WhatsApp > Settings > Account > Two-step verification > Enable.
The 2-step verification is already available on almost all email services, Twitter and other popular social media apps. This feature adds an additional layer of security — besides entering the account password one would also need to enter the verification code sent to the registered mobile number. However, when a user forgets the account, they can ask for an email to be sent to them to recover it. The email will ask if they want to disable the 2-step verification, and provides a link to that; once you click on it, this security feature is disabled, and the user once again gets access to their WhatsApp account.
As this is not a default feature we strongly recommend that you enable the 2-step verification feature not only for WhatsApp but for all the services you make use of.