Add section on organizations overview

Author: LauraBeatris

docs/guides/organizations/overview.mdx

@@ -67,6 +67,19 @@ To enable personal accounts for your application, toggle **Allow personal accoun
 > [!IMPORTANT]
 > Personal accounts being disabled by default was released on 08-22-2025. Applications created before this date will not be able to see the **Allow personal accounts** setting, because personal account were enabled by default.
 
+## Organization slug
+
+## Organization slug
+
+Organization slugs are human-readable URL identifiers that help users reference which organization they're working in.
+
+> [!IMPORTANT]
+> Organization slug is disabled by default for applications created after 10-06-2025. For applications created before this date, you can opt to disable it.
+
+To enable it on your application, toggle **Enable organization slugs** in the [**Organizations Settings**](https://dashboard.clerk.com/last-active?path=organizations-settings) page.
+
+If disabled, organization slugs won't be displayed in the [`<CreateOrganization />`](/docs/reference/components/organization/create-organization), [`<OrganizationList />`](/docs/reference/components/organization/organization-list), and [`<OrganizationSwitcher />`](/docs/reference/components/organization/organization-switcher) components.
+
 ## Active organization
 
 When a user is a member of an organization, they can switch between different organizations. The organization workspace that a user is currently viewing is called the **active organization**. The active organization determines which organization-specific data the user can access and which role and related permissions they have within the organization.