If the pod is in your current namespace, get the list of pods:
kubectl get pods
Pick a pod. Execute a bash session on it:
kubectl exec -it [POD_NAME] -- /bin/bash
Alternatively, find the pod you want in a different namespace:
kubectl get pods --all-namespaces
Pick a pod and execute a bash session on it:
kubectl exec -it [POD_NAME] --namespace [NAMESPACE] -- /bin/bash