The Device Enrolment Program is a functionality provided by Apple to control the activation process of devices (iPhone, iPad, Mac, Apple TV).
The typical screens a user needs to go through to set-up an Apple ID, define if its a new device, privacy, … can be controlled and facilitated. This is a great improvement in the user experience. We can fully configure a mobile device including apps and configuration without the need for a private Apple ID.
There is also a security aspect related to DEP: It is impossible to use a device outside the control of the company EMM.
A device (new or reset) can only finalize the activation process after entering the company credentials of the user. This makes it useless to thieves and avoids employees disabling the EMM controls.
This guide provides guidance on how to set-up an Apple DEP account.