Notification token for mulitiuser

I have configured notification.traccar.key for pushing notifiacation to Android Traccar Manager. For 3 users, key is the same or should be individual for each user? How should look traccar.xml config file with multiple notification keys?

You only need a single key.

Thank you Anton. The last question, how enable sound for event notification in WEB?

It's in settings / preferences somewhere.

I found. There are many sounds sample. Do they have different sounds?

There's only one sound.