Sending Excel files containing crucial financial and business data has risks. To add a layer of protection, you should learn to password protect an Excel file.

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.

How to lock cells in Microsoft Excel, so you need a password to change or erase data Written by Ryan Ariano ...

While password protection and encryption are excellent ways to secure your Excel workbook, they aren't foolproof and may cause compatibility issues with some third-party applications.