System overview
What is MDM lock?
MDM (Mobile Device Management) is Apple's enterprise device management capability. After an iPhone or iPad is enrolled and supervised, an authorized administrator can apply configuration profiles, install applications, enable lost mode, inspect device status and issue remote commands.
Why device rental businesses use MDM
Device rental operators can use MDM to maintain a device inventory, apply security policies, manage applications and respond to high-risk events. MDM should work together with identity verification, contracts, payment risk controls and user notices; it is not a replacement for a complete compliance program.
Supported Apple devices
The exact capabilities depend on the iPhone or iPad model, iOS or iPadOS version, enrollment method, Apple account status, certificates and current Apple policies.

For the complete Chinese explanation, see MDM监管锁与手机租赁设备管理介绍.