Select the cells you want users to be able to modify.
Choose Home> Cells> Format> Format Cells, which displays the Format Cells dialog box.
Click the Protection tab and deselect the Locked option. Click ok.
Optionally, choose Home> Cells> Format> Lock Cells. Because, by default, Excel locks all cells, choosing this option
turns the Lock Cells option off. Click the option again to turn on the Lock Cells option.