iCloud & iCloud Photos · Sharing folders and photo libraries
How do I share a folder in iCloud Drive with someone?
Short answer: In Finder, Control-click the folder in iCloud Drive, choose Share (or Collaborate), invite people and set whether they can edit or only view. Shared folders sync for everyone, and their contents count toward the owner's iCloud storage.
In Finder, Control-click the folder in iCloud Drive and choose Share (or Share → Collaborate), then choose how to invite people — Messages, Mail or a link — and whether they can make changes or only view. They need an Apple Account to join.
Shared folders appear in each person's iCloud Drive and stay in sync for everyone. You can change permissions or stop sharing from the same Share menu. Files in a shared folder count toward the owner's iCloud storage — see whose storage a shared folder uses.