The py launcher is optionally installed during the setup process when you first install Python on Windows. At one point, you’ll be prompted to do so, as per the screenshots shown below.

Download the latest Python version from python.org. Run the executable file. Now, click Install now, make sure to include PIP and IDLE and check “ Add Python to PATH”. You will be asked if you ...

During Python setup, you’re offered the option to install the py launcher, a small executable that lets you select (via command-line flags) which version of Python to use for a given script.

Python modules are typically installed using a package manager called 'pip', which launches a 'setup.py' file that is made available by the developer of the package for installation purposes.