The cis tagging component provides operations and structures to attach metadata, by means of tags, to vSphere objects to make these objects more sortable and searchable. You can use it to create, manage, and enumerate tags and their categories (the group a tag belongs to). You can also query the attached tags and attached objects.
The Category service provides operations to create, read, update, delete, and enumerate categories.
The Tag service provides operations to create, read, update, delete, and enumerate tags.
The TagAssociation service provides operations to attach, detach, and query tags.