https://www.python.org/downloads/release/python-342/ or https://www.python.org/downloads/release/python-278/. There is some incompatibility between the two so check which is the one you need. Then choose the Windows x86-64 (I assume you have 64-bit windows, if not use Windows x86 withouth the -64) .msi installer. Download and run the .msi file and it'll install the official Python executable on your computer.
The Python executable is available to any programs on your system (the installer should see to that) that want to run code written in the Python programming language so install it wherever you like.