Hello,
I hope you have done the necessary setup for using Python in MATLAB and imported numpy in your MATLAB code using the following:
py.importlib.import_module('numpy')
Otherwise, it might be an issue with the setup. It would be better to install Python (Cpython) and make sure that numpy library is installed. Then you can launch MATLAB and make sure that MATLAB has loaded Python using the following:
pyversion
If this does not work, it would be really helpful if you could give more details regarding your environment (if you are using Anaconda) and path setup.