To create an ARCoreSettings Asset and assign it to your build settings, open the Project Settings window (from Unity's main menu, go to Edit > Project Settings), then navigate to the XR Plug-in Management menu and check the ARCore provider, as shown in the screenshot below: This is useful if you want to provide different alternatives depending on whether AR is available.
If ARCore is optional, the Play Store lets users install your app on devices that don't support ARCore, or that support ARCore but don't have it installed. You can flag ARCore XR Plugin as either required or optional. Including the ARCore XR Plugin also includes source files, static libraries, shader files, and plug-in metadata. In most cases, you should use the scripts, prefabs, and assets provided by AR Foundation as the basis for your Handheld AR apps. However, this package doesn't expose any public scripting interface of its own. The ARCore XR Plugin implements the native endpoints required for building Handheld AR apps targeting Google’s ARCore platform using Unity's multi-platform XR API. For more information about this package, see the AR Foundation documentation. In addition, install the AR Foundation package, which uses ARCore XR Plugin and provides many useful scripts and prefabs. To install this package, follow the instructions in the Package Manager documentation. It doesn't support the following subsystems: This version of ARCore XR Plugin uses ARCore 1.22 and supports the following functionality: This package implements the following XR Subsystems: Use the ARCore XR Plugin package to enable ARCore support via Unity's multi-platform XR API.