Add Content Type Hub warning for list form configuration (#10694)

Author: Ashlesha-MSFT

docs/declarative-customization/list-form-configuration.md

@@ -1,7 +1,7 @@
 ---
 title: Configure the list form
 description: Configure list form with a custom header, footer and body with one or more sections.
-ms.date: 06/28/2022
+ms.date: 03/03/2026
 ms.localizationpriority: high
 ---
 
@@ -11,6 +11,9 @@ You can configure the list form in a list or library with a custom header, foote
 
 To configure a form, you will use JSON formatters that you are already familiar with when formatting a [column](column-formatting.md) or a [view](view-formatting.md) in a list or library. Form configuration allows for certain predefined elements and attributes to build the custom header, footer, and body with one or more sections.
 
+> [!IMPORTANT]
+> **Content Type Hub Considerations**: Custom form formatting JSON is stored on the list content type. Be sure that the content type you are customizing is set to allow edits at the site or list content type level before applying custom form formatting. This is highly likely to impact you if you are working with content types consumed from the content type hub, as these are read-only by default. You may need to temporarily set the content type to "Edit mode," apply your formatting, then return it to "Read mode."
+
 ## Get started
 
 To configure the form in a list or library: