Merge pull request #102662 from DCtheGeek/dmc-policy-ghi47019

Fixes MicrosoftDocs/azure-docs#47019 - Add note about read-only properties returned

Author: PRMerger7

articles/governance/policy/concepts/definition-structure.md

@@ -218,6 +218,12 @@ You use **displayName** and **description** to identify the policy definition an
 for when it's used. **displayName** has a maximum length of _128_ characters and **description**
 a maximum length of _512_ characters.
 
+> [!NOTE]
+> During the creation or updating of a policy definition, **id**, **type**, and **name** are defined
+> by properties external to the JSON and aren't necessary in the JSON file. Fetching the policy
+> definition via SDK returns the **id**, **type**, and **name** properties as part of the JSON, but
+> each are read-only information related to the policy definition.
+
 ## Policy rule
 
 The policy rule consists of **If** and **Then** blocks. In the **If** block, you define one or more