Numbers
Collaborate on a shared spreadsheet in Numbers for iCloud
Whether you’re the owner of a shared spreadsheet or you’ve been invited to collaborate, after you open the spreadsheet, you can see the edits made by others in real time, quickly jump to where people are editing, and more. The number of people editing or viewing the spreadsheet (not including you) appears beside the Collaboration button in the toolbar, and their names (or email addresses or phone numbers) appear in the participant list.