I would like to send, copy, export?? my library with an existing group that I am a member of. Is there a way to copy and paste my whole library to the group library?
In the Zotero desktop app or the beta version of the web library on Zotero.org, you can drag items or collections from My Library to the group library.
Just to correct what bwiernik said, it's not yet possible to copy collections across libraries in web library beta. That's because recreating collections structure is slightly more complicated than just copying items across (which web library can do). This is currently tracked for future release here: https://github.com/zotero/web-library/issues/227.
For the time being I'd advise using Zotero desktop app for this.
For the time being I'd advise using Zotero desktop app for this.