If you want to send a push notification to all the devices (both iOS and Android) or just to a single device, you have to go to the section Features -> Push Notifications on the Paperlit dashboard.
Add your message (max 140 characters) and add the UUID of the device where you want to test the notification. If you want to send the message to all the devices with the installed app, just leave the second field as is.
Select "Schedule" to schedule a date and time to send the message or send now to send it immediately.
Click Send and wait the notification!