How to apply policy initiative Azure

To properly define and assign an Azure Policy Initiative (Policy Set) using PowerShell, the JSON file must conform to the official initiative schema, and assignments are performed with the New-AzPolicyAssignment cmdlet. The error you encountered indicates that the JSON structure is invalid, policy definition references should not include a nested properties block. Instead, each reference must directly specify the policyDefinitionId and any required parameters.

https://learn.microsoft.com/en-us/azure/governance/policy/concepts/initiative-definition-structure

https://learn.microsoft.com/en-us/powershell/module/az.resources/new-azpolicyassignment?view=azps-15.4.0

https://learn.microsoft.com/en-us/azure/governance/policy/assign-policy-powershell