The General preferences pane controls Zotero's user interface, item import settings, file handling, and group library behavior.
By default, when you copy items between your personal My Library and a group library (or between different group libraries), any child notes, snapshots and other stored file attachments, linked URIs (to web pages or other programs), and tags are copied along. You can uncheck “child notes”, “child snapshots and imported files”, “child links”, or “tags” to prevent notes, attachments, links, or tags from being copied. Note that linked attachments are not supported in group libraries and will not be copied.