@Aditya Raina Thanks for posting in our Q&A. From your description, did you mean that you want to block imessage on iOS devices via intune? If there is anything misunderstanding, please correct me.
Based on my research, there is a setting "Block iMessage" under iOS device restrictions profile.
https://learn.microsoft.com/en-us/mem/intune/configuration/device-restrictions-ios#settings-apply-to-automated-device-enrollment-supervised-2
Please note that this setting applies to ADE enrollment devices and the devices are needed in supervised mode.
Hope it will help.
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