Share Multiple Files in a Folder Using Public Links
Where: This change applies to Lightning Experience in Professional, Enterprise, Performance, and Unlimited editions.
Why: Anyone with the link can view and download the files in the folder. You can change the folder’s contents at any time, and the changes occur in real time. To remove access to the folder, delete the link. To make the folder public again, create a new link.
How: Add the link in the folder’s row-level actions by clicking Public Link. Delete the link from the same dialog by clicking the trash can.
Chatter REST API supports folder sharing.