It's not feasible to manually maintain a large set of users in any enterprise level application. This is why every organization maintains a master source of all users on a server. So, Service-Now should be integrated with the master source to import users for user's access.
In many organizations, the Microsoft Active Directory server is used as the master source of employee or user records. Users are allowed to log into the assigned laptop or desktop using active directory's or Windows username and password. Service-Now provides an inbuilt Lightweight Directory Access Protocol (LDAP) server to integrate with Microsoft Active Directory to import all users' records. To step through this recipe, all you need is an active Service-Now instance and valid credentials and an admin role.