Pandoc is open-source software, maintained by volunteers working in their free time. Please keep that in mind when asking for help.
The first place to go if you have a question about pandoc, or if something doesn’t seem to be working properly, is to search the discussion forum. In all likelihood, someone has already asked a similar question and it has been answered. If not, you can ask your question there.
If you think you’ve found a bug in pandoc, you can create an issue on the github bug tracker. But unless you’re sure it’s a bug, it’s good to raise the issue on the discussion forum first. See the guidelines on contributing for some suggestions about how to write a useful bug report.
Suggestions for enhancements to pandoc (for example, new formats, options, or structural elements) should always be discussed on the mailing list before an issue is created on the github tracker.
People often ask questions about pandoc on stackoverflow. But the main pandoc developers do not monitor this site, so you’re likely to get better responses if you post on the discussion forum.