How is networking in domain model different than workgroup in accessing nod

in workgroup, account is necessary in each computer after that we can use it drive formatting/partition etc. in domain when we can login any computer what happens when we change in 1 pc what power we can have in domain to manage local resources and in domain what control user can have? list please. (2) active dir stores users pc printers etc- why we need active directory why admin require to locate a object/resource in 5000. how do we use active directory stored info (user name/group/printers/attributes/ in real scene.