How to send push notification even when the user is offline

As the title suggests, how do I send push notifications to a phone even when the user is not actively opening the game or app?
I’m trying to make an alarm app, and all I need is to send a notification to the user when they’re offline when the alarm is supposed to go off

I would be surprised if that would be even possible
To my understanding you would need some app to run in background to be able to pull that if that is even possible

If that’s the case, are there alternative ways to alert the player when they are offline? If not, thank you anyway. :+1:

When I open the pc i will give extension for the mobile notification