How Schema Markup Works
Most sites use JSON-LD based on Schema.org types and properties. Search engines decide which markup they support for search features.
A Simple Example
A glossary can describe its index as a DefinedTermSet and each entry as a DefinedTerm even when that markup does not create a special Google rich result.
Why Schema Markup Matters
Valid markup can clarify page meaning and enable supported search features.
Common Misreading
Schema is not a ranking shortcut. Markup must match visible content, and using a Schema.org type does not guarantee a rich result.