Hello!

You can just create an account on wikitech.wikimedia.org and get access. https://wikitech.wikimedia.org/wiki/Help:Access has more information. Then you'll need to be added to whichever project you want to work on. If this is tool labs, tools.wmflabs.org has a form that you can use to request access. If it is a different project, someone already involved in that project should be able to add you to it. If you want a new project, there is a link on the sidebar of wikitech.wikimedia.org for you to request that.

Thank you :)