Get WhatsApp Messenger
Pros 
- It can be used anywhere in the world, as long as you have an internet connection
- WhatsApp allows you to create group chats and conference calls with up to 256 people
- All messages, calls, and even files shared on WhatsApp are secured with end-to-end encryption
- The app is regularly updated with new features and improvements.
Cons 
- Requires internet
- Limited file size.