The feature allows you to create a six-digit pass-code that’ll be required whenever your phone number is being verified on the app. The two-step verification feature can be activated by heading to Settings ==>Account ==> Two-step verification ==> Enable.
The feature also allows you to add your e-mail address, something which is optional but can be useful in case you ever forget your pass-code.
Keep in mind that WhatsApp won’t verify the accuracy of the email address you enter, so you need to enter it carefully to make sure that you’re not locked out of your account if you forget your pass-code.
Whatsapp latest version that has this feature has started rolling out. You should get an update waiting for you. Just head-over to your respective App Stores to update your Whatsapp Application, so you can get this feature Enabled.