Telegram

Next to Whatsapp, Telegram is the biggest messaging application out there with more than a 100 million users. Their biggest selling point is the fact that it uses end to end encryption making it impossible to for someone to intercept a message.
 
Also, Telegram users will be able to access their messages from any platform that is supported, so much so that you can start a message on one platform and finish it in another. Users will never lose the data ever again.
 
Telegram is known for its ability to use the least amount of data for messages, it uses a combination of 256-bit symmetric AES encryption, 2048-bit RSA encryption, and Diffie–Hellman secure key exchange, and it comes with support for group chats for up to 5,000 people.
 
As you can imagine, it has an exhaustive collection of stickers and emoji, so you’ll never run out of things to say.