https://setuptools.pypa.io/en/latest/userguide/quickstart.html#basic-use
When creating a Python package, you must provide a pyproject.toml file containing a build-system section similar to the example below:
[build-system]
requires = ["setuptools"]
build-backend = "setuptools.build_meta"
This section declares what are your build system dependencies, and which library will be used to actually do the packaging.
In addition to specifying a build system, you also will need to add some package information such as metadata, contents, dependencies, etc. This can be done in the same pyproject.toml file, or in a separated one: setup.cfg or setup.py.