Are web-push notifications (PWA) supposed to work natively?

[JP TTT]

We already set the System > Settings > Web App > Manifest configuration. 

We need to set something else additionally. A third-party service like OneSignal? Or tweak any hosting server configuration / library?

Edited May 10 by JP TTT

[Jim M]

Nope, just need the manifest set and PHP GMP enabled/installed. Setup the PWA on your device and go to Account Settings -> Notification Settings -> under "Push", click "Enable in this browser"