The License Service is in the Platform Services Controller. The License Service provides common license inventory and management capabilities to the vCenter Server systems that are registered to a Platform Services Controller or multiple Platform Services Controllers that are joined in one vCenter Single Sign-On domain.
During the upgrade of the vCenter Server systems that are connected to a Platform Services Controller, their licensing data is transferred to the License Service. The licensing data includes the available licenses and license assignments for hosts, vCenter Server systems, Virtual SAN clusters, and other products that you use with vSphere.
After the upgrade or migration of the vCenter Server systems completes, the License Services stores the available licenses and manages the license assignments for the entire vSphere environment. If your vSphere environment consists of multiple Platform Services Controllers joined in one vCenter Single Sign-On domain, the License Service in every Platform Services Controller contains a replica of the licensing data for the entire environment.
For more information about the License Service and managing licenses in vSphere, see vCenter Server and Host Management.