Delete shared notes on iCloud.com
In Notes on iCloud.com, select the shared note that you want to delete.
If you don’t see the notes list, see Show the folder or notes list in Notes on iCloud.com.
Tap in the toolbar, then tap OK.
One of the following happens:
If you’re the owner: The note is removed from the devices of everyone you shared it with. You can recover your recently deleted notes from your Recently Deleted folder.
If you’re a participant: The note is removed from your notes list, but not the owner’s notes list or any other participant’s notes list. The note doesn’t move to your Recently Deleted folder. You can open and edit the note again by tapping the original link that the owner shared, unless the owner stopped sharing the note.