What are examples of structured vs unstructured data?

Structured data refers to information in “tables”, data with a known schema.

E.g.

EmployeeManagerSalary
SmithJones5000
ChangSmith6000

Unstructured data on the other hand refers to information which has no clear structure, e.g. text from books.

That being said, usually data is just semi-structured, linguistics still has some structure for text, and bullets.