If you enable workbook protection for a document, from now on no more changes to the worksheet register can be made in the document. Also the commands of the Insert | group Tables | Sheet button are no longer available.
This has the following effect:
▪Users can't add worksheets anymore.
▪Users can't copy, delete or rename worksheets anymore.
▪Users can't hide/unhide worksheets anymore.
Choose the command Review | group Protection | Workbook protection 
to enable the workbook protection. To disable it, choose the same command once more.
For more information, see the next pages.