As shared in the Files sharing Query blog, a file can be shared with users, groups, records, and the content library.
Let's see how the system works when uploading a file from a record related list.
By default, when a file is loaded from a record, the user who uploaded the file becomes the File Owner, and the record owner has extra permissions compared to other users; this applies when default file access is set to Set by Record, check this article.
File owner:
Users with edit access to the record <-- similar to the record owner
Users without edit access to the record:
Users with permission "Modify ALL records" or "Modify ALL data" <-- similar to file owner
Additionally, users with "Create Public Links" permission
The user will be able to share the file externally with an expiration date and a password:
Who Can Access?
Click the Share dropdown from the Files related list, and you can see "who can access"? Remember the "Set by Record" mentioned earlier, and the ShareType in Query is "I", not "V".
SELECT Id, ShareType, ContentDocumentId, ContentDocument.Title, LinkedEntity.Name, LinkedEntity.Type FROM ContentDocumentLink WHERE ContentDocumentId = '069VZ000006928nYAA'
Share the file with a Library
What happened when we shared the file with a library?
Notice that the share type for the record and the user who shared earlier has changed to Viewer. When a file is added to a library, it means that access to the file follows access to the library; this setting can’t be changed. You can't manually re-share the file to the user as a Collaborator. You also can't remove the file from the Library. Vote for this idea. But, if you have a folder in a library, you can move the file within the library and the subfolder.
Reference:
