Prevent unauthorized changes to data by protecting worksheets. In a protected worksheet, none of its contents can be changed. However, it’s possible to set up the worksheet so that only certain cells and elements can be changed after it's protected.
By default, cells are locked once a worksheet is protected. If there are cells that users should be able to change after a worksheet has been protected, make sure to unlock them before you protect the worksheet.
Select the cells you want to unlock.
Click the Format button on the Home tab.
Select Format Cells.
Click the Protection tab.
Clear the Locked check box.
You can also toggle the lock on and off by clicking the Format button and selecting Lock Cell.
Locking and unlocking cells only takes effect once the sheet is protected.
The selected cells will now stay unlocked and editable by others after the sheet is protected.