How do I build a react-native app so that it runs as an ipad app on an ipad?
you can use this command
react-native run-ios --simulator="iPad Pro (9.7-inch)"
Visit https://facebook.github.io/react-native/docs/running-on-simulator-ios.html
As of Xcode 9.3.1, you have to go to Build Settings and select Targeted Device Family 1,2
if you want to support both the iPad and iPhone.