To scale certificate management, it is critical to distribute the responsibility of managing certificates to the teams that need them. To do this effectively, often a self-service model is used, teams are considered "customers" of a platform team that provides the Kubernetes infrastructure (including certificate management). This multi-tenant model removes the bottleneck of a single team managing certificates for everyone.
However, to be successful, the platform team should guide its customers to follow best practices, and ensure that certificates are issued in a secure and consistent way. These best practices and rules are what we call "policy". Currently, cert-manager distinguishes between three types of policy: