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If you are talking about creating a custom service it can be done with any method available to ASP.NET. I would personally recommend Web API as it returns really clean data that's easy to work with. Here's a link to a partner blog post on how to do this in Sitefinity.
With this method you can use the API to query and return any information you need from module builder using the Code references that were generated with your module builder module.
I hope this helps.
No problem and welcome to Sitefinity!
You can navigate to your module builder module under Administration > Module Builder > [Your Module Name].
From there look at this screenshot.
I hope this helps!