What is differents between Jupyterhub and simple Jupyter?
I want you describe in more detail
By "simple Jupyter", I assume you mean a local installation/environment in which you are running Jupyter Notebook. JupyterHub is simply "a multi-user version of the notebook designed for companies, classrooms and research labs"—essentially just a piece of server-side infrastructure provided by the Jupyter project to help deploy a Jupyter environment for easy connection and use by multiple distributed clients.
Once connected, up and running, the interface and user experience is quite similar, except with JupyterHub it is running on a server somewhere that you usually connect to by pointing your browser to an external URL, instead of localhost or a specific address/port like you would use for a local Jupyter Notebook.