Hy friends I am going to tell my true experience about whatsapp which I use since last 4 years.
Concept of whatsapp- the concept of whatsapp is very simple that send or recieve message secret.
Layout and design - it design and layout are very much simple to understand amd use it any one can use this app to send or recieve their messages.
Features and function-its main function and feature is it can send message in text or voice. It is safe because anyone cant message you. only those can message whom contact are saved in your phone and those who saved your.
Useful- it is very useful app for sending messages