Excell program on new iPad

Further clarification of comments offered by sberman and ChrisJ4203...

Most MS 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.

In addition to what sberman has said, you need to have a Microsoft account to be able to enter data into Excel. If you do not have an account, you would either need to get one, or use Numbers, which is Apple's free spreadsheet program. If you have a Microsoft Account, you can download the latest version of Excel app from the App Store, and then log in with your Microsoft Account and you will be able to create spreadsheets and enter data in Excel.

You likely had a very old version of Excel previously. Microsoft moved to Office 365 quite a few years ago.

https://www.microsoft.com/EN-US/microsoft-365/buy/compare-all-microsoft-365-products?icid=MSCOM_QL_M365