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.

At the file level, you can password protect an Excel workbook in two ways: You can determine who can get in and who can save changes.

Open the spreadsheet you want to protect in Excel, click the "Review" tab and then click "Protect Sheet" in the Changes group to display the Protect Sheet dialog.

Need to keep a file confidential? Microsoft Word and Excel make it simple to assign a password.