Use shared notes or folders and manage participants carefully.
Direct answer
Collaboration and note locking have different purposes. Apple’s current guidance says a shared iCloud note cannot be locked, and Smart Folder conversion also has restrictions involving shared folders and locked notes.
Choose one primary job
Use eligible locked notes in a non-shared location.
Share a sanitized copy instead of exposing the private master note.
Before sharing
Review the note body, title, attachments, participant list, and destination account. Remove private history and credentials rather than assuming a lock will travel with the shared item.
