If you intend to publish Mathematics, you can either submit the article to a peer-reviewed journal such as Bulletin of the AMS or arXiv, or self-publish.

If you plan to publish on your own, I recommend getting a book on TeX and install a TeX distribution on a free operating system such as Debian GNU/Linux, Fedora Linux, or Ubuntu.

If you plan to publish Mathematics on the World Wide Web, learn TeX and MathJax.

$Q.E.D.$