What EXIF can contain
Common fields include the camera and lens model, date and time, exposure, aperture, ISO, focal length, orientation, and sometimes GPS coordinates. A file does not need to contain every field, and values can be changed or removed.
Why EXIF matters
Photographers use EXIF to study settings and organize work. The same data can also expose a capture date, editing workflow, or location. Check the final file you will publish rather than assuming an earlier copy and an exported copy match.