React 19 introduces game-changing features like Actions API, useOptimistic Hook, Metadata API, and <Form> Component.Actions API simplifies defining server actions and enhances code separation with built-in form support.useOptimistic Hook allows updating the UI pre-server response, providing real-time user experience.Metadata API brings native SEO support, eliminating the need for react-helmet and ensuring SEO is integrated.<Form> Component simplifies form handling without context juggling or custom handlers, making it user-friendly.