If you have installed Jupyter notebook in your system and still getting an “‘Jupyter-lab’ is not recognized as an internal or external command, operable program or batch file.” then this quick tutorial is for you. Please follow the below steps:
Step 1: First of all confirm whether Jupyter lab is install or not using the below command.
Python –m jupyter --version
Step 2: If you are able to see jupyter lab as shown in the above screenshot then run the python –m notebook command. This will open and jupyter notebook windows on the browser.
python –m notebook 
Step 3: If the notebook is not opened in the browser by default, copy the URL from the command line and paste it into the browser address bar it will open the notebook.
Now you will be able to code python in a jupyter notebook.
Happy Coding !!!