The most basic example of a GETPIVOTDATA formula in Microsoft Excel is when the function is used to retrieve a grand total of ...

Instead of typing direct cell references (such as B2) into your formula, if you click cell B2, Excel will insert the column name into the formula to create a structured reference.

Here is a tutorial to lock or hide only the formula cells in an Excel workbook. You can also lock formulas in all worksheets in a workbook.