How to Protect a workbook file from viewing or editing in Excel?

1. On the File menu, click Save As.
   
2. On the Tools menu, click General Options.
   
3. Do either or both of the following:
   
   • If you want users to enter a password before they can view the workbook, type a password in the Password to open box, and then click OK.
     
   • If you want users to enter a password before they can save changes to the workbook, type a password in the Password to modify box, and then click OK.
4. When prompted, retype your passwords to confirm them.
   
5. Click Save.
   
6. If prompted, click Yes to replace the existing workbook.