WhatsApp is one of the most popular application in android mobile. It is a messenger by which we can send text message, PDF file, Photos, Videos, Contact, Location, GIF file totally free of cost. For use this app we don’t need any money we need only Internet. On playstore it has 1 billion downloads. It is working on 2G, 3G, 4G and Wifi net also. We can use WhatsApp on our desktop, laptop by whatsApp web. Recently WhatsApp launch it’s voice call and video call felicity so for this its became a complete communication system. It is very easy to use and it used very cheap internet. So it is the most popular and useful application.