Issue about Protected workbook and cell editing function

[batman7570]

Would like to ask for your suggestion for this case:
Once the sheet is protected, the cell cannot be edited when I come back to it

Let me input text: test1

When I try to edit again, the original text would be deleted and the cell is blank

Anyway I can fix that? Even the workbook is protected?

 

[sparky2205]

If you want to edit the cell on a protected worksheet then the cell needs to be unlocked. All cells are locked by default.
Press Ctrl+1 then on the Protection tab untick Locked and press OK.