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.

There are several options available to you to protect your Excel file with a password. Remember that once you protect the Excel file, you cannot open it without entering the password.

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.

Type the password into the "Password to unprotect sheet" field and click "OK." Re-enter the password when prompted and click "OK" to protect the spreadsheet. Press "Ctrl-S" to save the changes.

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 ...

If you want Excel to prompt for a password to open the file, enter a password in the "Password to open:" field.