Get Firebase Key
Firebase
Firebase Key is needed to enable Firebase Push Notifications.
Obtain Firebase Key
If you have completed your Firebase Configuration then follow the below steps otherwise complete the Firebase Configuration
Open your Firebase Console and Click on Project Over View → Project Settings
In Cloud Messaging Tab you'll see Cloud Messaging API
if you have not enabled Cloud Messaging enable it by clicking on Pop up Menu shown in Screenshot in step 2.
copy the Server Key after enabling Cloud Messaging.
Add Firebase Key To Admin Panel
On Admin Dashboard Go to Settings → App Configuration Settings
Add your Web API Key in Firebase Key Key field.