Python 3 3.6 How to download and install Packages and Modules with pip

Python 3 3.5 3.6 How to download and install Packages and Modules pip pip3
1)
For python 3 and above

sudo apt-get install python3-pip python3-dev

*Install
sudo pip3 install requests

*Uninstall
sudo pip3 uninstall requests

2)
For Python 2.7
sudo apt-get install python-pip python-dev

*Install
sudo pip install requests

*Uninstall
sudo pip uninstall requests

3)
For virtualenv
*Activate
$source myenv/bin/activate

*Install
$sudo pip install requests
OR
$sudo pip3 install requests