Hello @pananag,
Push notifications can be quite complex (see How integrate Notification push with Nakama and Unity - #2 by shprot), so we usually recommend using a third party provider such as OneSignal which makes it easier to send push notifications across the different providers. You can call the OneSignal APIs within your custom Nakama logic.
Alternatively, you could use the Nakama In-App system to show or schedule OS notifications from within the client app itself, but it depends on what you’re looking to achieve.
Best.