What is the primary method for enrolling macOS devices into MDM?

The primary method for enrolling macOS devices into Mobile Device Management (MDM) is through the Device Enrollment Program (DEP), which has been integrated into Apple's MDM solutions, or manually using the System Preferences application. This method facilitates a streamlined enrollment process, allowing organizations to manage devices easily once they have been purchased through Apple or a participating reseller.

Using DEP allows for a more automated and efficient setup by enabling devices to be enrolled automatically when they are first activated, thus reducing the administrative burden. Additionally, manual enrollment through System Preferences provides an option for devices not procured through DEP, allowing administrators to still configure and manage macOS devices effectively.

The other methods listed are not primary enrollment techniques for MDM on macOS devices, as they either do not pertain to MDM enrollment directly or offer less utility in bulk management scenarios. This makes the approach involving DEP and the manual method via System Preferences the most relevant and effective for enrolling macOS devices into MDM.