Two-step verification is an optional feature available in WhatsApp introduced recently to enable more security to your account. If you haven’t set it up yet, here are the steps to enable WhatsApp’s two-step verification.

Step 1:  Click on the three dots on the top right of your WhatsApp, from the menu that appears Select Settings. Then Navigate to Account and then select Two-step verification

                      

Step 2: Click on Enable and you will be asked to enter a 6 digit number as your passcode. You will need to enter it twice.

                      

Step 3: Third step is to enter an email address, which will act as a recovery option in case you forget your passcode. Enter the email address twice and click the Save button. Please make sure to provide an accurate and active email address. 

                     

Now the two-step verification is enabled on your WhatsApp account and you may click the Done button to finish the process.

enable WhatsApp's two-step verification                     

Once it is enabled, you will have options to disable, change the passcode, and change the email address.