Azure Notification Hubs enable viewing telemetry data in the Azure portal.
https://stackoverflow.com/collectives/azure/articles/75613990/azure-notification-hub-understanding-the-key-metrics-telemetry
You can target specific devices by their InstallationIds when sending a push notification. However, at the moment, Azure Notification Hubs does not support sending to multiple specific InstallationIds in a single send operation.
https://learn.microsoft.com/en-us/azure/notification-hubs/configure-notification-hub-portal-pns-settings?tabs=azure-portal
A common workaround is to tag devices with unique tags (such as their InstallationId) and then send the notification to multiple tags. This achieves essentially the same result. The notification is distributed to all registrations that have any of the tags specified by the Notification Hubs service.
As per the first point, you can use the telemetry data provided by Azure Notification Hubs to check the success or failure of notifications for each device. The per-notification outcome push trace provides detailed information on whether each notification succeeded or failed.