macOS supports extensive metadata which can help you search, sort and more, through Spotlight in particular. Adding metadata to files isn’t as straightforward as it could be, though. With the exception of Finder Comments, most metadata can only be added by apps. If you want to add copyright information to a mixture of different document types, there has been no simple solution, apart from my free SearchKey and SearchKeyLite apps, which handle a narrow range of metadata types.
Metamer changes this by giving you full access to 16 of the most useful metadata types: ApplicationCategories, Authors, Comment, Copyright, Creator, Description, FinderComment, Headline, Information, Keywords, Kind, Languages, Projects, Subject, Title, and Version. Unlike when using my full-blown extended attribute editor xattred, you don’t have to know anything about how the metadata are stored.
To add metadata to a document, any other file, or a bundle like an app, open it in Metamer.
Drop down its Combo box menu to select which type of metadata you want to add or edit. Add the text content of that type, and click on the Save button.
If you want to use it to add or edit an extended attribute (xattr) which isn’t in its list, simply type in the full name of the xattr, and enter its content. Metamer only handles xattrs which are stored as property lists containing text, but those include the great majority which are accessible through Spotlight, for instance.
Metamer version 1.0 runs on all versions of macOS from El Capitan to Catalina, and is available from here: metamer1
from Downloads above, and from its Product Page. It uses my auto-update mechanism, making updating to the next version simpler.