This is the best livechat plug in I could find

Good chat. Nice looking and easy to install. Chat appearance could be easily styled to match website design. Loads very fast and asynchronously. Doesn’t increase overall page loading time at all. Chat has photo/video, emoji and file upload support. Uploaded files are shared across all chat users and hosted on chat servers and doesn’t require any space at your hosting which is important for me since I don’t have much space at my hosting.

You can play with demo chat at https://www.chatbro.com/en/ before decide to install or not.