First version of the code to create an anchor in AR Foundation based on the ARRaycastHit.

ARPlaceHologram.cs

ARAnchor CreateAnchor(in ARRaycastHit hit)
{
    ARAnchor anchor;

    // ... here, we'll place the plane anchoring code!
    
    // Otherwise, just create a regular anchor at the hit pose

    // Note: the anchor can be anywhere in the scene hierarchy
    var instantiatedObject = Instantiate(_prefabToPlace, hit.pose.position, hit.pose.rotation);

    // Make sure the new GameObject has an ARAnchor component
    anchor = instantiatedObject.GetComponent<ARAnchor>();
    if (anchor == null)
    {
        anchor = instantiatedObject.AddComponent<ARAnchor>();
    }
    Debug.Log($"Created regular anchor (id: {anchor.nativePtr}).");

    return anchor;
}