The metadata information of Creator of a file is quite self-explanatory. The Creator states who is responsible for the existence of the file resp. who made it.
For images, this might be the person that shot the photo or created the graphic. For documents, it’s usually the person that wrote the content. This also applies to e-book files. However, for e-books and documents, the meta information of the author is more common. For audio files, the creator might be the producer or recording person. It’s also possible, that the Creator is used instead of the more common metadata band or artist.
In some cases, the Creator of a file isn’t necessarily a person. This metadata tag can also contain information about the software, program or even (online) service that was used in order to create the file. In these cases, the metadata often contains information about the nature of the Creator, such as “creator tool” or “creator software”.
The Creator is not necessarily also the owner of the file as rights of creative or scientific work can be given to another person, company or institution.