Protect a Worksheet’s Data: If you will be distributing a workbook to other people, you can enable Excel’s options for safeguarding worksheet data by activating the sheet’s protection feature. You can also configure the worksheet to require a password to unprotect it.
There are two main methods you can use to safeguard worksheet data: You can unlock only those cells that users are allowed to edit, and you can configure a range to require a password before it can be edited.
Protect a Workbook’s Structure and Windows: You can prevent unwanted changes to a workbook by activating protection for the workbook’s windows and structure. You can also configure the workbook to require a password to unprotect it.
You should protect a workbook’s structure when you do not want others to perform actions such as adding or deleting worksheets; you should protect a workbook’s windows when you do not want others to perform actions such as splitting a window or freezing panes.