@SivaSankaRao
You can enable encryption of all VMs in the resource group by uncommenting line 211 of the Azure Disk Encryption prerequisites PowerShell script.
The backup policy did not get attached to your question. I recommend posting this as a separate question as azure-backup is handled by a separate team. They should be able to provide assistance.
Hope this helps! Let me know if you run into any issues or have more questions regarding encrypting your VMs.
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