Before start you have to know what is the different between download packages and install packages ... why you have to use download or install packages ...
What are the differences between downloading and installing packages using pip3?"
Answer :
* Downloading packages retrieves the package files to your local storage without making them usable in Python code.
* Installing packages not only downloads them but also adds them to your Python environment, making them available for use in Python code.
now to install or download packages you have to open terminal window :
1- type next CLI : pip3 install "type package name " OR pip3 download "type package name "
* if you are looking to uninstall packages you have to type :
1- pip3 uninstall "type package name "