If you enable workbook protection in a document, you can no longer make any changes to the worksheet register in it. Furthermore, the commands of the Insert | group Tables | Sheet button are no longer available.
The main effects of this are as follows:
▪Users can no longer add worksheets.
▪Users can no longer copy, delete or rename worksheets.
▪Users can no longer show/hide worksheets.
Choose the command Review | group Protection | Workbook protection 
to enable workbook protection. You can also disable it again with the same command.
For more information, see the following pages.