Go to File > Info > Protect Document > Encrypt with Password. Type a password, press OK, type it again and press OK to confirm it. Save the file to make sure the password takes effect.

How to protect an Excel file using a password to prevent unwanted access to your data.

You can add a password to an Excel file to prevent unauthorized users from opening or modifying it.

You can add a password to an Excel file to prevent unauthorized users from opening or modifying it.

You can add a password so that only authorized users can modify a presentation. Unauthorized users can still open the presentation and then save it by using a different file name.

To add a new password, click Protect Sheet or Protect Workbook, type and confirm the new password, and then click OK. To remove a password from the workbook, click Protect …

Use a password to help protect your Outlook data file (.pst) so that others who share your computer can't access your data.

You can help keep your private notes safe from prying eyes by protecting a OneNote notebook section with a password. When a section is password-protected, all of its pages are locked …

In this topic we’ll discuss the various ways you can utilize the primary options to protect and distribute your Excel files.

Add a password to protect your entire workbook and control whether others can open or make changes to it. Protect your file by setting passwords for Open and Modify.