diff --git a/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/examples/createLegacySubscription.json b/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/examples/createLegacySubscription.json
index 65ad499728a9..e0e193269f79 100644
--- a/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/examples/createLegacySubscription.json
+++ b/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/examples/createLegacySubscription.json
@@ -12,7 +12,13 @@
         {
           "objectId": "67439a9e-8519-4016-a630-f5f805eba567"
         }
-      ]
+      ],
+      "additionalParameters": {
+        "customData": {
+          "key1": "value1",
+          "key2": true
+        }
+      }
     }
   },
   "responses": {
diff --git a/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/examples/createSubscription.json b/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/examples/createSubscription.json
index 84f6fd17ba23..4483cd796e9d 100644
--- a/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/examples/createSubscription.json
+++ b/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/examples/createSubscription.json
@@ -10,6 +10,12 @@
       "costCenter": "135366376",
       "owner": {
         "objectId": "973034ff-acb7-409c-b731-e789672c7b32"
+      },
+      "additionalParameters": {
+        "customData": {
+          "key1": "value1",
+          "key2": true
+        }
       }
     }
   },
diff --git a/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/examples/renameSubscription.json b/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/examples/renameSubscription.json
index c673259dde23..0c7f7c131eb7 100644
--- a/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/examples/renameSubscription.json
+++ b/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/examples/renameSubscription.json
@@ -3,7 +3,7 @@
     "subscriptionId": "83aa47df-e3e9-49ff-877b-94304bf3d3ad",
     "api-version": "2019-10-01-preview",
     "body": {
-      "SubscriptionName": "Test Sub"
+      "subscriptionName": "Test Sub"
     }
   },
   "responses": {
diff --git a/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/subscriptions.json b/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/subscriptions.json
index a065c890aa85..8605058478c8 100644
--- a/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/subscriptions.json
+++ b/specification/subscription/resource-manager/Microsoft.Subscription/preview/2019-10-01-preview/subscriptions.json
@@ -542,6 +542,13 @@
             "MS-AZR-0017P",
             "MS-AZR-0148P"
           ]
+        },
+        "additionalParameters": {
+          "description": "Additional, untyped parameters to support custom subscription creation scenarios.",
+          "type": "object",
+          "additionalProperties": {
+            "type": "object"
+          }
         }
       }
     },
@@ -571,6 +578,13 @@
         "managementGroupId": {
           "description": "The identifier of the management group to which this subscription will be associated.",
           "type": "string"
+        },
+        "additionalParameters": {
+          "description": "Additional, untyped parameters to support custom subscription creation scenarios.",
+          "type": "object",
+          "additionalProperties": {
+            "type": "object"
+          }
         }
       }
     },