If you didn't know, every Stack Exchange site has a responsive layout - meaning that if you access the desktop site on a mobile device, it will render in a mobile-optimized format. Most views, including the homepage, questions, and search render in this view, though some pages may have been ported over not yet.
We used to offer official mobile apps, but those are no longer available for any platform. These apps are no longer supported and the supporting infrastructure has been taken down, so existing installations no longer work.
If you strongly prefer a native app over using the website, some third-party developers have written some apps that you may be able to use to view the site; however, due to API limitations, not all features may be supported:
Still looking? Try browsing all the apps available at Stack Apps.