Users hoping to join the WhatsApp call service in the near future can do so today by receiving a call from an already-initiated user. This means that you’re going to either need to know someone who already has calls active OR you’re going to have to head to a Google+ group (or something similar) to get someone to call you. This invite program has had its ON switched flipped off and on several times over the past couple of weeks – at this moment, it’s up and running.
Gaining access with two different WhatsApp accounts won’t necessarily allow you to empower call functionality. You’ll need one account that already has said functionality to bring it to the other.
If you have a friend with calling abilities, you’ll need them to call you to make the process happen.
WARNING: If you receive the following message from any one of several social networks (Facebook, Google+, Twitter, etc), DO NOT accept. This is malware and not to be trusted.
“Hey, I’m inviting you to try WhatsApp Free Voice Calling feature, click here to activate now.”
Only trust people you KNOW to send you a call with WhatsApp – don’t trust strangers with this invite!