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.

The Protect Sheet and Protect Workbook options are available under the Review tab. If you prefer them, select a relevant option to protect your Excel file content and structure.

Want to protect an important Word document or Excel spreadsheet? Here's how to add a password, make documents read-only, and tap into other tricks to safeguard sensitive files.

Microsoft Excel lets you embed content from other applications, including PDF files. You can embed a PDF file into a cell of an Excel worksheet and then use Excel's security features to lock the ...

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.

Here is a tutorial to lock or hide only the formula cells in an Excel workbook. You can also lock formulas in all worksheets in a workbook.