Apple'sUser Enrollmentworkflow is specifically designed for BYOD scenarios, andaccount-driven User Enrollmentmakes this even simpler. Apple Learning specifies that the required element is aManaged Apple Accountissued through Apple Business Manager or Apple School Manager. When a user signs into Settings with their Managed Apple Account, the iOS or iPadOS device automatically recognizes the account type and begins the enrollment process. This streamlines the workflow by removing the need for downloaded configuration profiles or certificates. Unlike Device Enrollment, User Enrollment establishes a cryptographically separated environment where organizational data and personal data remain isolated. This balance gives IT control of apps, calendars, and email while protecting the user's privacy. Thus, the Managed Apple Account is the key to enabling account-driven User Enrollment.
References:Apple Platform Deployment - "User Enrollment with Managed Apple Accounts."