However, if you’ve noticed, you’d find that there is no official WhatsApp app for desktop. This basically covers all the smartphones out there and you should be able to run the app on your phone without any issues. The WhatsApp app is available for almost all the popular mobile platforms including iPhone, Android, and Windows Phone. The app uses your phone number as your ID and lets you have chats, voice calls, and even video calls with the contacts you have on your smartphone. With more than a billion active users, WhatsApp is the fastest growing instant messaging app all around the world.