How protection to an Excel sheet (How do I protect an Excel sheet?)

In excel, workbook may be set several safe degrees, the highest safe is to whole file. It cotrols that an user can open a file, or not.
Usually, you have to set password that open it, specifically, steps are following:
open your file--click' Tools'---'protection'---select one option which you want: 1. 'protect sheet' for only protection a sheet; 2. 'Allow user Edit Range' for setting protection to some part of sheet; 3.'protect workbook' is to set protection to whole workbook; 4.'Protection and Share Workbook' is for sharing it, it can't be edited by users ---to set a your password is over.