can't add text to excel sheet in M365

On Android, Excel can open many file types but only some can be edited. If a workbook opens but does not allow typing or changes, the file is likely in a format that Excel for Android treats as read-only, or contains features that force read-only behavior.

Check these points:

1. Confirm the file type
   • Excel for Android can open and edit only certain formats:
     • .xlsx (Excel workbooks)
     • .xlsb (non-XML binary workbooks)
     • .xlsm (macro-enabled workbooks, but VBA functions will not run)
   • Many other formats are read-only on Android, for example:
     • .xls (older Excel format)
     • .csv
     • .ods
     • .xlt, .xltx, .xltm
   • If the file is one of these read-only formats, save it as an .xlsx workbook on a desktop version of Excel, then reopen it on the phone to edit.
2. Check for features that make the workbook read-only on mobile
   • On some mobile platforms, Excel workbooks become read-only if they contain certain features such as:
     • Unsupported functions
     • Data validation
     • Array formulas
     • Data tables
     • Slicers
     • Macros enabled
     • OLE objects or ActiveX controls
   • If the workbook has any of these, open it in desktop Excel, remove or simplify those features, save as .xlsx, then try again on the phone.
3. Verify subscription and app state
   • Core editing is available for free on mobile, but premium features require a qualifying Microsoft 365 subscription. Ensure the Microsoft 365 subscription is active and the user is signed into the Excel app with that account.
   • If editing suddenly stopped working around a renewal or update, uninstall and reinstall the Excel app on Android, then sign in again.

If after converting the file to .xlsx, removing advanced features, and confirming subscription/sign-in the workbook still opens read-only, open it in desktop Excel or Excel for the web to check for protection (worksheet or workbook protection) and remove it there before editing on the phone.

References:

• Why can't I open my Excel file?
• Office Mobile for Windows Phone
• Microsoft 365 mobile apps
• I have been using Excel for IPad for over a year and suddenly it has stopped working. - Microsoft Q&A
• My Microsoft365 Office Package no longer works with my iPad Pro - Microsoft Q&A
• I am unable to open and create documents - Microsoft Q&A
• Excel unable to edit - Microsoft Q&A