Tox is a simple and secure communication software, based on distrubited network with end to end encryption enabled. And also It has features that most other softwares have, instant message, voice/video calls, screen sharing, file sharing, group chat.
You can download Tox from https://tox.chat/, and add groupbot to find firends and join groups.
Why should I use Tox? You know people in countries such as North Korea, China, Iran are monitored by the government, and they can't visit social media websites outside the country. As far as I know, all foreign communication softwares such as Telegram, Line, Wire, WhatsApp are blocked in China. Tox has no central severs that can be raided, shut down, or forced to turn over data. No other people can see your message except you and the person you are talking to.
If you don't want being monitored any more, or get tired of personal privacy leaking, you should definitely try Tox, and it is completely free and comes without advertising forever.