You can create a group and invite others to join. Then you can collaboratively develop one Zotero library, and/or share your individual libraries. Group members must have Zotero accounts. Zotero has good documentation on this: Zotero Groups
. (Note: your group collections appear below your personal collections in the left hand Zotero panel. If you have many collections, you may have to scroll down to see your Group collections).
You can drag and drop citations from your personal collections to Group collections
This creates a new and entirely independent citation – not just a new ‘view’ of the same citation.
That means changes made to a citation in a personal collection (for instance, fixing title capitalization) do not propagate to the same item in the Group collection (and vice versa).