Some of my friends are big fans of WhatsApp, and have noted that I don't (and won't) use it, so I just wanted to briefly provide the major reasons why:
- It's owned by Facebook (and connected to the Facebook platform) and there are some major privacy concerns
- Since acquisition by Facebook, there have been major security concerns
Due to similar problems, I advise against using similar apps like Apple iMessage, Google Hangouts, Facebook Messenger, Telegram, etc.
If you're really keen on using a "Whatsapp-style" secure messaging app (with group messaging, voice calls, etc.), there is an alternative that is free, open source, and run by a non-profit organization.
It's called Signal and can be found at: https://signal.org/
I have it installed, so feel free to send me a test message to try it out, and let me know if you have any further questions about the various privacy and security concerns with some of these other messaging apps.