Fortunately, Excel provides built-in features that allow you to hide and password-protect your worksheets without requiring any programming skills. Password Protecting Excel Spreadsheet Data ...

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.

You can have Excel make a spreadsheet in read only format for others, so that people can read its contents but not edit them, or you can enforce other content restrictions.

Four ways to protect your Excel formulas (free PDF) If a user inadvertently changes the formulas in your Excel workbooks, all your hard work could go out the window.