pip install python 3

## To install Pip, first download get-pip.py from:
https://bootstrap.pypa.io/get-pip.py
  
## Then run the following command in the command line
## in the folder where the file has been saved.
python get-pip.py

[server]$  python3 -m pip install

pip install package name

python -m pip install <package>

#Download Selenium
python -m pip install selenium

curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py

You cannot just pip install python3 because it is not a library.

If you want to install the latest python3:
https://www.python.org/ftp/python/3.8.2/python-3.8.2.exe 

sudo apt install python3-pip

pip3 install <package_name>