This repo contains an example and a tutorial how to build a documentation on-line on readthedocs.org for a python code internally documented with NumPy docstrings. You'll notice that it is itself built using Readthedocs.
>>Get started! Access the tutorial on readthedocs: here>> https://py-code-docs.readthedocs.io/en/latest/index.html.
If you don't wish to share your code nor its internal docstrings, and you just wish to publish an "external" documentation about it, you can switch to the simpler tuto corresponding better to your case here.