User provisioning is the process of setting up user accounts for access to your different enterprise systems. In this provisioning process, you also allocate privileges and permissions to the users, so as to protect the security of the enterprise systems, while allowing users access to everything they need to do their work, and nothing more.
Ideally, as with Identity and Access Management (IAM) systems, there is one digital identity (account) per individual, and that one user account is used for accessing the different enterprise systems. IAM systems are also known as Single Sign-On.