examples of semi structured data ? i read that Json or XML are unstructured data; Are Json or XML data or are they tools to tag the data?

I understand from this wikipedia page (https://en.wikipedia.org/wiki/Semi-structured_data) that semi structured data are data without a formal database structure, but still have some tags;
JSON and XML are not tools. They are data formats. For example, to find out more about JSON you can look up the RFC description that specifies how to format JSON files:

https://tools.ietf.org/html/rfc7159

It explains how to tag the data. Then there are tools that validate JSON, and XML files to see if they conform to the requirements, or there are tools that convert JSON into another format or read it into memory into some object or class.