Add change plans documentation to Customer Center (#1018)

* Add change plans documentation to Customer Center

* nits

* add link to section

Author: facumenzella

docs/tools/customer-center/customer-center-change-plans-ios.mdx

@@ -0,0 +1,36 @@
+---
+title: Configuring Change Plans for Customer Center (iOS)
+sidebar_label: Change Plans (iOS)
+slug: customer-center-change-plans-ios
+hidden: false
+---
+
+:::info REQUIREMENTS
+Customization requires iOS SDK version 5.33.0 or later. Earlier versions of the SDK support change plans but without customization options - all products in the subscription group will be shown.
+:::
+
+![Customer Center Change Plans Configuration](/docs_images/customer-center/customer-center-change-plans.png)
+
+Change Plans allows iOS customers to switch between different subscription products directly within the Customer Center. This feature provides a seamless experience for users who want to upgrade, downgrade, or modify their current subscription.
+
+This setup enables RevenueCat to automatically present the appropriate product change options based on a user's current subscription, providing a streamlined experience for product modifications.
+
+The SDK will automatically display available product options based on the user's active subscription and the products configured in your subscription group.
+
+You can configure which products will be offered as a product change, instead of showing all the products within the subscription group. Rather than showing all available products, you can choose a specific subset of subscriptions to offer as change options for each product.
+
+**This feature works for products within the same subscription group.**
+
+## Configuration
+
+After setting up your subscription group in App Store Connect, you need to configure which specific products should be available for changes in the Customer Center settings.
+
+For each subscription group, you can select a subset of products to offer as change options rather than displaying all products in the group. You must select at least 2 subscriptions per group to enable product changes.
+
+**Important**: If your subscription group has 2 or fewer products, the configuration is automatic and all available products in the group will be shown as change options. Manual configuration is only available for subscription groups with 3 or more products.
+
+In the Customer Center Configuration, when selecting the **Change Plans** path, you can specify exactly which products should be presented as change options for each subscription group.
+
+[Learn more about configuring the Customer Center.](/tools/customer-center/customer-center-configuration)
+
+

docs/tools/customer-center/customer-center-configuration.mdx

@@ -16,7 +16,7 @@ There are four main management options available in Customer Center. These optio
 - Cancellation
 - Missing Purchases
 - Refund Request (iOS only)
-- Plan Changes (iOS only)
+- [Plan Changes](/tools/customer-center/customer-center-change-plans-ios) (iOS only)
 
 When a customer initially opens the Customer Center, these are the main options they'll see to select from.
 

sidebars.ts

@@ -357,6 +357,7 @@ const customersCategory = Category({
           items: [
             Page({ slug: "customer-center-promo-offers-apple" }),
             Page({ slug: "customer-center-promo-offers-google" }),
+            Page({ slug: "customer-center-change-plans-ios" }),
           ],
         }),
         SubCategory({