By default, protecting a worksheet locks all cells so none of them are editable. To enable some cell editing, while leaving other cells locked, it's possible to unlock all the cells.
To prevent other users from accidentally or deliberately changing, moving, or deleting data in a worksheet, you can lock the cells on your Excel worksheet and then protect the sheet with a password. Say you own the team status report worksheet, where you want team members to add data in specific cells only and not be able to modify anything else.
When sharing your worksheets with other people or sending your Excel files outside of your organization, you may want to prevent other users from changing cells that shouldn't be changed, and also from moving or deleting important data in your worksheet or workbook.