The Sitecore Forms application allows content editors to apply conditional rendering logic to form fields based on other fields’ value. This creates a dynamic form where users are shown less or more fields based on conditional logic.
This functionality comes out of the box with Sitecore. It isn’t, however, an out of the box feature of the React JSS application. Instead, it requires manual setup.
Learn more about Sitecore Forms and JSS: Conditional Logic in React.