IPython is an awesome project which provides a much better Python shell than the one you get from running $ python in the command-line. It has many cool functions (running Unix commands from the Python shell, easy copy & paste, creating Matplotlib charts in-line, etc.) and I'll let you refer to the documentation to discover them.
IPython is a kernal for Jupyter Notebook. If you are confused iPython with Jupyter, refer to thd Jupyter documentation
$ pip install ipython
If you want a more fine grained command you can try the following:
For zsh -> $ pip install 'ipython[zmq,qtconsole,notebook,test]'
For bash -> $ pip install ipython[zmq,qtconsole,notebook,test]