By default, iOS and iPadOS apps launch in portrait mode. If you'd like to change this setting, you can set the default launch orientation in your app's Info.plist file:
Add the key
UIInterfaceOrientation (Initial Interface Orientation) to your Info.plist file.
Possible values are:
If you want to go a step further and limit which orientations your app supports, you can add the key
UISupportedInterfaceOrientations Supported Interface Orientations to your Info.plist file. Supported Interface Orientations accepts an array of values. Enter each value from the list above that your app should support.