Hi Vinod, it's a matter of device type as Rahul stated. Android can be enrolled with Zero-Touch configuration method, but all devices must meet some requirements, you can read all the steps and prerequisites here: https://learn.microsoft.com/en-us/mem/intune/enrollment/android-dedicated-devices-fully-managed-enroll#enroll-by-using-google-zero-touch
Apple devices can be enrolled without user intervention with Automated Device Enrollment, as for Android ones, also this method requires some prerequisites: https://learn.microsoft.com/en-us/mem/intune/enrollment/device-enrollment-program-enroll-ios
Keep in mind that devices of both platforms must be enrolled as Corporate-Owned and needs to start fresh.
Android devices need to be Android Enterprise ones.
Apple devices involves the agreement and purchase from Apple Business Manager.
Userless intervention approach should be considered in scenario with many devices and branch offices, personally I don't reccomend it under 100 units.
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