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.

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.

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 ...

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.

Add a password and expiry date to an Excel sheet link If you use Microsoft's OneDrive cloud platform to save and share Excel files, you can password-protect and set an expiry date for a shared link.

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.

You worked hard to put that Excel sheet together, now protect it from unintended damage.