Miro Community uses Sphinx for documentation, which translates reStructuredText files into HTML, PDF, or other formats. The canonical documentation is compiled and made available on readthedocs, but you can also use Sphinx to compile the documentation on your local development machine.
If you don’t feel like you can write very well, don’t sweat it. Write what you can, and pass it off to someone else to improve. The first draft of a piece of documentation is hard to write simply because it doesn’t exist. Writing it can give someone else a great starting point.
Here are some good resources on writing documentation: