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

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.

Remember that, with password protections removed, anyone with access to your Excel file can open, view, and edit it. If you've decided a password isn't necessary anymore, this likely isn't an issue.

Getting Excel to prompt with a read-only recommended message or password field is a straightforward process requiring little more than learning the location for these settings.