I think it is well known app, I dont have to write much. I have switched from SMS to WhatsApp to send and receive messages, calls, photos, videos, and Voice Messages.
- NO ADDITIONAL FEES: WhatsApp uses your phone’s Internet connection (4G/3G/2G/EDGE or Wi-Fi, as available) to message and call friends and family, so you don’t have to pay for every message or call.
- MULTIMEDIA: Send and receive photos, videos, and Voice Messages.
- WHATSAPP CALLING: Call your friends and family using WhatsApp for free, even if they’re in another country. WhatsApp calls use your phone’s Internet connection rather than your cellular plan’s voice minutes.* (Note: you can’t access 911 and other emergency service numbers through WhatsApp).
- GROUP CHAT: Enjoy group chats with your contacts so you can easily stay in touch with your friends or family.
- WHATSAPP WEB: You can also send and receive WhatsApp messages right from your computer’s browser.
- NO INTERNATIONAL CHARGES: There’s no extra charge to send WhatsApp messages internationally. Chat with your friends around the world and avoid international SMS charges.
- SAY NO TO USERNAMES AND PINS: Why bother having to remember yet another username or PIN? WhatsApp works with your phone number, just like SMS, and integrates seamlessly with your phone’s existing address book.
- OFFLINE MESSAGES: Even if you miss your notifications or turn off your phone, WhatsApp will save your recent messages until the next time you use the app.