GitHub Marketplace is a platform where many actions and GitHub Apps are hosted and developed. You can also publish actions created with PyAction there.
To do this, ensure that your action's slug (action repository name) is unique. Check the following URLs and make sure they all result in 404 pages.
-
https://github.com/<action_slug> -
https://github.com/orgs/<action_slug> -
https://github.com/marketplace/actions/<action_slug>
For the next steps, I recommend following the official documentation.