Excel offers numerous levels of protection for your work.   You can protect a whole workbook, worksheet, columns, rows or even individual cells. If you want to prevent other user opening your whole workbook, then it you need to protect it.  It’s easy to do.

Choose File- Save As- Options.

We want to password protect the whole workbook Enter a password to modify- enter a password, this will prevent anyone opening, saving or making changes to the workbook unless you know the password to the workbook.

Click OK.