If you have sensitive data you'd like to keep from prying eyes in a Microsoft Excel file, the easiest way to protect it is with Excel's built-in password tools.

Microsoft Excel lets you embed content from other applications, including PDF files. You can embed a PDF file into a cell of an Excel worksheet and then use Excel's security features to lock the ...

If you would like to make sure that your Excel spreadsheet data is secure this guide will show you how to password protect and hide worksheets ...

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.