You can lock cells in Excel by heading into the program's "Protection" tab. There, you can set a password, and protect your data.

Creating a macro in Microsoft Excel allows you to program automatic tasks into a spreadsheet or template that can contain multiple commands or functions for easy access and use. After these macros are ...

Formulas are one of the most important components of an Excel sheet and as such, deserve–warrant–protection. You don’t want users accidentally changing formulas and impacting the purpose of your work.