<http://Schema.org|Schema.org> itself has very little restrictions as it's just a dictionary of machine-readable terms. It is up to each individual consumer of <http://schema.org|schema.org> annotations to formulate how annotations should be provided, as Google does in its <https://developers.google.com/search/docs/appearance/structured-data/search-gallery|feature guide>.
For example
1. `OnlineStore`: <https://developers.google.com/search/docs/appearance/structured-data/organization#technical-guidelines>
2. `WebSite`: <https://developers.google.com/search/docs/appearance/structured-data/sitelinks-searchbox#adding-structured-data>