Best answer
If your business and website are brand new and you don't have an audience or don't know where it hangs, Tawk.to is a great option for a start, as it's free.
However, if you already have an audience, you should care about it and allow your clients to reach you on a platform they are more comfortable with, as
@DediRock said. In this case, it's better to look for a chat solution that provides omnichannel integrations. For example, LiveChat allows you to integrate Facebook chat, WhatsApp, Instagram, Telegram, Viber, and many other platforms through which clients or prospects can reach you. It's comfortable for everybody – the clients can reach you on a platform that they are more comfortable with, and you store all that communication in one single dashboard.