Managed Apple IDs are accounts that are tied to the same organization as the VPP Program Facilitator users who manage VPP licenses.
In such case, the MDM server chooses to instruct the VPP service to associate Managed Apple IDs with the given VPP users. When Managed Apple IDs are associated with the VPP users, the MDM server no longer sends out invitations (email or push) to users and wait for them to accept the device prompts.
Students with Managed Apple IDs created in Apple School Manager do not need to accept any prompts to install applications and books on devices. Workspace ONE silently accepts these prompts on the Managed Apple ID's behalf with no admin interaction.
For more information, refer the Managed Distribution by Apple IDs section in the Integration with Apple Business Manager guide.