WhatsApp Messenger is a really good app for instant messaging over the internet.
It allows sending voice messages, text messages and attaching of contacts and pictures.
Also, it allows calls to other WhatsApp users.
It also has a very good collection of emojis ranging from expression ones to those depicting objects.
Also, WhatsApp Messenger has recently been made free for lifetime which is really helpful.
Overall, an excellent app for messaging and calling over the internet.