Navigate to Zoho Sheet, the free online Excel viewer (see Resources). Click the "Browse" button in the Local File section, select the XLS file and click "Open." Click the "View" button to view the ...

To enable or disable Office Viewer integrated in the Microsoft Edge browser, toggle the switch against 'Open Office Files in the browser' setting.

While you won't be able to edit Excel files with the iPad's Quick Look file viewer, you will be able to view them and even copy and paste data from them.