Hi there!
I don't have any experience on freelancer.com since I did not win project yet. But I am experienced developer and web administrator. I have created dozen of joomla websites for my customers and I still administer it.
I am familiar with html, css, joomla, article editors,... all skills that are required for article submission.
If this is possible long term work, I could submit one article for free, and in that way you could easily test my skills. After that you could decide will you hire me or not.
Best regards!