- Install the Zotfile plugin
Tools -> Add-ons -> Install Add-on From File... - Zotfile Preferences
Location of Files -> Choose... Select a cloud storage folder such as iCloud - Zotero Settings
Preferences -> Advanced -> Files and Folders -> Root Directory for Attaching Linked Files -> Choose... Select the cloud storage folder chosen earlier - File Settings
Select all items -> Right-click -> Manage Attachments -> Rename and Move - Syncing across multiple devices
Repeat the above settings on other Zotero devices.