diff --git a/docs/deployment_string.md b/docs/deployment_string.md
index f1a5b8ddc..364f4ff58 100644
--- a/docs/deployment_string.md
+++ b/docs/deployment_string.md
@@ -74,6 +74,7 @@ Because {{site.data.keyword.edge_notm}} uses operators to deploy the application
 
 - `operatorYamlArchive`: The content of the operator yaml archive files. These files are compressed (tarred and gzipped). And then the compressed content is converted to a base64 string.
 - `metadata`: A list of key-value paries. It is for internal use only. Do not put it in the `clusterDeployment` when publishing a service. 
+-  `mmsPVC`: `"mmsPVC": {"enable": true, "pvcSize": 20}` - enable persistent volume claim for the service to receive models deployed using the Model Management System (MMS) with the desired size in GB. Default size is 10GB
 
 ## Deployment String Examples
 {: #deployment-examples}
@@ -122,7 +123,11 @@ A `clusterDeployment` string JSON would look like this when defining a service u
 
 ```json
 "clusterDeployment": {
-  "operatorYamlArchive": "/filepath/k8s_operator_deployment_files.tar.gz"
+  "operatorYamlArchive": "/filepath/k8s_operator_deployment_files.tar.gz",
+  "mmsPVC": {
+    "enable": true,
+    "pvcSize": 20
+  }
 }
 ```
 {: codeblock}
@@ -130,6 +135,6 @@ A `clusterDeployment` string JSON would look like this when defining a service u
 When the content is encoded and stringified, the above would look like:
 
 ```json
-"clusterDeployment": "{\"operatorYamlArchive\":\"H4sIAEu8lF4AA+1aX2/bNhDPcz4FkT4EGGZZsmxn0JuXZluxtjGcoHsMaIm2uVKiRlLO0mHffUfqjyVXkZLNcTCUvxeLR/J4vDse7yQ7w4ikjD8MT14OLuBi4ppfwP6vefb86Xji+ZOL6fjE9byRNz1BkxeUqUImFRYInQjOVde4vv7..."
+"clusterDeployment": "{\"operatorYamlArchive\":\"H4sIAEu8lF4AA+1aX2/bNhDPcz4FkT4EGGZZsmxn0JuXZluxtjGcoHsMaIm2uVKiRlLO0mHffUfqjyVXkZLNcTCUvxeLR/J4vDse7yQ7w4ikjD8MT14OLuBi4ppfwP6vefb86Xji+ZOL6fjE9byRNz1BkxeUqUImFRYInQjOVde4vv7...\",\"mmsPVC\":{\"enable\":true,\"pvcSize\":20}}"
 ```
 {: codeblock}
diff --git a/docs/service_def.md b/docs/service_def.md
index 2e743dc85..e082fee47 100644
--- a/docs/service_def.md
+++ b/docs/service_def.md
@@ -49,3 +49,11 @@ The differences are noted below.
 - `deploymentSignature`: The digital signature of the deployment field, created using an RSA key pair provided to `hzn exchange service publish`. It is a best practice to ALWAYS use the `-K` option when publishing a service, to ensure that the public key used to verify this signature is available for the agent to verify the signature.
 - `clusterDeployment`: The Kubernetes Operator yaml for this service. See [deployment structure](./deployment_string.md) for more information on this field. In `display` form, this field is shown as stringified bytes and truncated. This field MAY be omitted if `deployment` is provided. The yaml files of a published service can be retrieved from the exchange using `hzn exchange service list -f <downloaded-yaml-file>`.
 - `clusterDeploymentSignature`: The digital signature of the clusterDeployment field, created using an RSA key pair provided to `hzn exchange service publish`. It is a best practice to ALWAYS use the `-K` option when publishing a service, to ensure that the public key used to verify this signature is available for the agent to verify the signature.
+
+## Service using MMS in edge cluster
+
+The following three user inputs are only for a service using MMS deployed to the edge cluster:
+
+- `MMS_K8S_STORAGE_CLASS`: to indicate the Kubernete storage class of the PVC for the service. If not specified the service will use the same storage class as cluster agent.
+- `MMS_K8S_STORAGE_SIZE`: to indicate the size of PVC in GB. This user input value will overwrite the value specified in the `clusterDeployment` in the service definition.
+- `MMS_K8S_PVC_ACCESS_MODE`: to indicate the PVC access mode. The values are: `ReadWriteOnce` or `ReadWriteMany`. If not specified in the user input, the service will use the same PVC access mode as cluster agent.
\ No newline at end of file