For more information about Twisted, please see the Twisted Project page.
You can get the latest release from PyPI Twisted project page.
You can get older releases from PyPI archives or Twisted download site.
The recommended way is to run pip install Twisted, preferably inside a virtualenv.
If you are installing on macOS, pip install Twisted[macos_platform] will install the macOS-specific requirements.
If you are installing on Windows, pip install Twisted[windows_platform] will install the Windows-specific requirements.