Answers for "why we create virtualenv in python"

create a virtualenv python

pip install virtualenv
cd projectfolder #go to project folder
virtualenv projectname #create the folder projectname 
source projectname/bin/activate

setting p a virtual envioronment

#Creating a Virtual Environment | Windows 10
#Proceed to the folder were you want to create your environment, Then enter the following:
...> py -m venv project_name
#To activate the environment, run:
...> project_nameScriptsactivate.bat
#Then install Django using pip
...> py -m pip install Django