Wrote a tutorial

How to apply Client ID enforcement policy to your Mule app in API Manager


Now that we know how to apply API Autodiscovery to our Mule application, learn how to apply one of the most popular policy: Client ID enforcement. In summary, this policy restricts the call to your API by using client ID/secret values. We’ll set this up using Basic Auth to be able to pass Username and Password to our API.

https://developer.mulesoft.com/tutorials-and-howtos/getting-started/client-id-policy/