Excel worksheet input issue on iPad

Microsoft Productivity Apps for iPad (such as Word, Excel, PowerPoint) offer limited functionality without an Office 365 Subscription - but only for devices with a screen size of 10.1” or less.

Devices with larger screens only permit you to view (but not create or edit) an existing document.  Full App functionality requires an active Office 365 Subscription.

If forcing the Excel app to quit and relaunching it doesn't fix the problem, try deleting the app and reinstalling. If that still doesn't fix the problem, you'll probably need to contact Microsoft Support for assistance.

Regards.