A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
All cells on an Excel worksheet are locked by default, but this only becomes effective when the worksheet is protected.
So you have to take two steps:
First, select all cells that the user should be able to edit.
Press Ctr+1 to activate the Format Cells dialog.
Activate the Protection tab.
Clear the Locked check box.
Click OK.
All cells that you did NOT select will remain locked.
Then, activate the Review tab of the ribbon and click Protect Sheet.
Use the check boxes to specify what the user should be able to do.
At the very least, leave the check box 'Select unlocked cells' ticked.
If you want to specify a password that will be needed to unprotect the sheet later on, enter it (and do not forget it!)
Click OK. If you provided a password you will have to enter it again as confirmation.
Users will now only be able to edit the cells that you unlocked.