Add read tags to the tags article

Author: mumian

articles/azure-resource-manager/management/tag-resources-bicep.md

@@ -3,7 +3,7 @@ title: Tag resources, resource groups, and subscriptions with Bicep
 description: Shows how to use Bicep to apply tags to Azure resources.
 ms.topic: conceptual
 ms.custom: devx-track-bicep
-ms.date: 09/26/2024
+ms.date: 05/14/2025
 ---
 
 # Apply tags with Bicep
@@ -136,6 +136,24 @@ resource applyTags 'Microsoft.Resources/tags@2021-04-01' = {
 }
 ```
 
+## Read Tags
+
+You can read existing tags with the following approaches.
+
+> [!WARNING]
+> The `tags` property on the `Microsoft.Resources/tags` resource is not set if there are no tags set.
+> To avoid errors, ensure you use the safe-dereference operator (`.?`) on `properties`.
+
+```Bicep
+resource readTags 'Microsoft.Resources/tags@2021-04-01' existing = {
+  name: 'default'
+}
+var tagValue = readTags.properties?.tags?.myTag
+
+// Equivalent to above:
+var tagValue2 = reference(subscriptionResourceId('Microsoft.Resources/tags', 'default'), '2021-04-01', 'Full').properties.?tags.?myTag2
+```
+
 ## Next steps
 
 * For a list of resource types that support tags, see [Tag support for Azure resources](tag-support.md).