Structured data adds standard labels to a webpage so software can identify things such as products, articles, and organizations. It is often written as JSON-LD using the schema.org vocabulary.
Search engines can use supported structured data for richer search listings, such as product details. The labels should match information people can see on the page. Adding them does not guarantee a rich result or an AI citation.
For example, Product markup can label a visible product name, price, and availability. Article markup can label an article's author and publication date. The type should fit the page and follow the search engine's rules for that feature.
Google says no special structured data is required to appear in AI Overviews or AI Mode. It remains useful for search features that explicitly support it, but clear, accurate page content matters on its own.