You can send notification messages using the Notifications composer in the Firebase console. Though this does not provide the same flexibility or scalability as sending messages with the Admin SDK or the HTTP and XMPP protocols, it can be very useful for testing or for highly targeted marketing and user engagement.
The Firebase console provides analytics-based A/B testing to help refine and improve marketing messages.
After you have developed logic in your app to receive messages, you can allow non-technical users to send messages per the instructions on the Notifications page in the Firebase Help Center.