With a fresh install of macOS, it comes with a version of Python, but it doesn’t come with Python’s package manager, pip.
If you need to use pip, it is fairly easy to install.
First you’ll want to install the command-line tools by either installing Xcode or running this command from Terminal:
$ xcode-select --install
Once the command-line tools are installed, you’ll run this command:
$ sudo easy_install pip
Installation should be fairly quick. Afterwards running pip -V should return something like:
$ pip -V
pip 8.1.2