diff --git a/docs/extensibility/extending-blocks.md b/docs/extensibility/extending-blocks.md
index 7f5587c5b3bf56..f442ec58e8df79 100644
--- a/docs/extensibility/extending-blocks.md
+++ b/docs/extensibility/extending-blocks.md
@@ -21,6 +21,8 @@ wp.blocks.registerBlockStyle( 'core/quote', {
 
 The example above registers a block style variation named `fancy-quote` to the `core/quote` block. When the user selects this block style variation from the styles selector, an `is-style-fancy-quote` className will be added to the block's wrapper.
 
+By adding `isDefault: true`, you can make registered style variation to be active by default when a block is inserted.
+
 ### Filters
 
 Extending blocks can involve more than just providing alternative styles, in this case, you can use one of the following filters to extend the block settings.