The Device Enrollment Manager (DEM) is a kind of service account. These accounts have permissions that let authorized users enroll and manage multiple corporate-owned devices. A DEM account requires an Intune user or device license, and an associated Azure AD user.
DEM is an Intune role/permission that can be applied to an Azure AD user account, and they can enroll up to 1000 devices. A DEM account is useful for scenarios where devices are enrolled & prepared before handing them out to the users of the devices. There's a limit of 150 Device Enrollment Manager accounts in Microsoft Intune. DEM enrolls Windows 10/11 devices.
How to deploy the MSI package to an enrolled device through Microsoft Intune.