In a nut shell, not to get to technical.
VoIP stands for Voice over IP. It takes voice transmission, your voice, and turns it into data transmissions over the internet, or over a network. This allows for multi-purposing of the high speed data connection, I.E. the internet.
So do not be confused by the term VoIP. It is just another form of communication transmission. Imagine the days before telephone. People would yell to speak long distances, or send a “Runner”. Just think, someone probably said, “that telephone thing is going to put runners out of business someday”.