Integrate LDAP to work with the Active Directory in your instance to use global user authorization data. Set up and use Single-Sign-On (SSO) technology so that users use their profiles in other services to sign in to their instance.
Delegation is the ability to give other users the access to view and interact with tasks and approvals assigned to other user, and to receive copies of all their notifications.
Impersonate other authenticated users for testing purposes. As an impersonator, you have the access to exactly what the other user can access in the system.