Excel's Protect Sheet capability can prevent users from changing cells, and it can hide formulas from view. For example, say you want to give users the ability to enter data in a worksheet for analysis, but you want to keep the proprietary formulas used in the analysis from being visible.

By default, the Protect Sheet feature locks all cells from data entry. To unlock cells for data input, follow these steps:

1. Select the cells for data input, and click Format | Cells.
2. On the Protection tab, deselect the Locked check box, and click OK.
To hide formulas from view, follow these steps:
1. Select the formula cells you want to hide, and go to Format | Cells.
2. On the Protection tab, select the Hidden check box, and click OK.
3. Go to Tools | Protection | Protect Sheet, and click OK. You can also set a password to prevent others from unprotecting the sheet.