Apps on GitHub extend and improve existing workflows. People can purchase apps from GitHub Marketplace or browse useful tools and services that integrate with GitHub in Works with GitHub.
You can build GitHub Apps and OAuth Apps. For information on choosing a type of app, see "Getting started with building apps" and "Differences between GitHub Apps and OAuth Apps."
GitHub Apps: Use the GitHub Platform Forum for support requests, bug reports, and discussions. The forum allows you to collaborate with other integrators as well as engineers and product managers from GitHub.
OAuth Apps: Contact GitHub support directly.