Android 13 - Notification Permissions

// Declare the launcher at the top of your Activity/Fragment:
private final ActivityResultLauncher<String> requestPermissionLauncher =
        registerForActivityResult(new ActivityResultContracts.RequestPermission(), isGranted -> {
            if (isGranted) {
                // FCM SDK (and your app) can post notifications.
            } else {
                // TODO: Inform user that that your app will not show notifications.
            }
        });

// ...

private void askNotificationPermission() {
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.POST_NOTIFICATIONS) ==
            PackageManager.PERMISSION_GRANTED) {
        // FCM SDK (and your app) can post notifications.
    } else if (shouldShowRequestPermissionRationale(Manifest.permission.POST_NOTIFICATIONS)) {
        // TODO: display an educational UI explaining to the user the features that will be enabled
        //       by them granting the POST_NOTIFICATION permission. This UI should provide the user
        //       "OK" and "No thanks" buttons. If the user selects "OK," directly request the permission.
        //       If the user selects "No thanks," allow the user to continue without notifications.
    } else {
        // Directly ask for the permission
        requestPermissionLauncher.launch(Manifest.permission.POST_NOTIFICATIONS);
    }
}

 https://firebase.google.com/docs/cloud-messaging/android/client