Try command pip install qiskitpip install qiskit
or pip3 install qiskitpip3 install qiskit
in cmd or Anaconda Prompt to install the qiskit module. Then try running the command you used.
If it's still not working check whether your notebook is working in the same location where you installed the qiskit module.
Tip: Use "from qiskit import*"from qiskit import *
as it saves time and imports all the packages in qiskit.
Alternative: You can also use the jupyter notebook in IBM Quantum Experience.