To start gaming you will need the following:
Now that you got your fancy input device all set up, you're probably looking for games to play that support gampads.
Start by checking out the currently most popylar controller enabled games or find games that suit your needs via our all controller enabled games page.
iOS 13 is not released yet. At the time that we're writing this post, there's only a developer beta, which is not recommended to install on consumer devices, additionally you'll need a paid Apple Developer account to use it on your device. If you are the impatient type, you are probably better off waiting for the iOS public beta, which will release in July of 2019. If you want to play it safe, wait for the official iOS 13 release which will be in September of 2019.