feat(framework): Add workflow channel preferences docs

sdks/framework/typescript/steps/introduction.mdx

@@ -137,3 +137,42 @@ type ProviderOverrideOutput = {
 ```
 
 The `_passthrough` object and the known provider values are deeply merged prior to sending the request to the provider, with the `_passthrough` object taking precedence.
+
+
+### Workflow channel preferences
+
+By default, Novu will show the subscriber preferences in the Inbox component. Subscribers can enable/disable any active channel in the workflow using subscriber preferences.
+With Workflow channel preferences you can control what the default preference for a channel is and also if subscriber can change it.
+
+You can specify inApp, sms, email, chat and push in channels object, each of these takes an object with defaultValue that controls if a channel is enabled/disabled by default for subscriber.
+The readOnly property controls if subscriber can change if a channel is enabled/disabled. 
+
+ReadOnly and defaultValue on workflow object is used for a channel that is not specified in channels object so if a new channel is introduced in workflow and specific preferences for that channel is specified these will be used instead. 
+
+These preferences can also be controlled from the Novu dashboard on a workflow, click on the cog and then preferences to do this.
+
+```typescript
+const newWorkflow = workflow(
+  'hello-world-preferences',
+  async ({ step }) => {
+    await step.inApp('send-in-app', () => ({
+      subject: 'Welcome!',
+      body: 'Hello there',
+    }));
+  },
+  {
+    preferences: {
+      workflow: {
+        defaultValue: false,
+        readOnly: true,
+      },
+      channels: {
+        inApp: {
+          defaultValue: true,
+          readOnly: true,
+        },
+      },
+    },
+  }
+);
+```