This part of the documentation describes how to get the API Key in the 360 Client Hub.
To get the API Key in the 360 Client Hub:
Log into the 360 Client Hub. You will need a valid user account for this.
Once all of the steps from the Setup Process are successfully completed, you can generate an API Key.
When the phone number has the status "DONE" the "Generate API Key" button will be enabled. If you click on the button, you can generate an API Key which will be displayed in the browser.
For safety reasons, the API Key will show up only once. Make sure to store the key in a safe place before you close the window.
By clicking "Generate API Key" it will revoke any existing keys and create a new API Key.