How to edit Kubernetes cluster values for OIDC?

You should be using kube-apiserver.

The Kubernetes API server validates and configures data for the api objects which include pods, services, replicationcontrollers, and others. The API Server services REST operations and provides the frontend to the cluster’s shared state through which all other components interact.

kube-apiserver [flags]

If using kops, run kops edit cluster and add:

spec:
  kubeAPIServer:
    oidcIssuerURL: ISSUER_URL
    oidcClientID: YOUR_CLIENT_ID

If you are using kube-aws, add following to cluster.yaml:

       oidc:
         enabled: true
         issuerUrl: ISSUER_URL
         clientId: YOUR_CLIENT_ID

You can read more about setup of on here, you might also consider using Kubelogin

EDIT:

kube-apiserver is running as a Docker container on your master node. Therefore, the binary is within the container, not on your host system. It is started by the master's kubelet from a file located at /etc/kubernetes/manifests. kubelet is watching this directory and will start any Pod defined here as "static pods".

To configure kube-apiserver command line arguments you need to modify /etc/kubernetes/manifests/kube-apiserver.yaml on your master.