WebRTC is designed for high-performance, high-quality communication of video, audio, and arbitrary data. In other words, for apps exactly like what you describe.
WebRTC is mainly UDP, with WebRTC you may achieve low latency and smooth playback which is crucial stuff for VoIP communications.
When building a video/audio/text chat, webRTC is a good choice since it uses peer-to-peer technology and once the connection is up and running, you do not need to pass the communication via a server (unless using TURN).
Webrtc is a part of peer to peer connection
It is perfect for use cases such as voice and video calls, online conferencing, and chat.