Where is the right place to render a React app?

Question

React

I started learning React, I had a question, why not render the entire application in the body? They say there will be problems with the Google font loader and scripts. How then can I do it correctly, if there should be one root container. After all, I first need to render the header, ... , footer, I don’t have to do it all in . Maybe I misunderstood, and you can render more than one container and it will be correct. Maybe I don't understand react correctly? Is it necessary (is it right to do this?) Is it possible to do absolutely the entire site using react, if not, then what? <div class="root">