Yes, there is, and it's simple & clearly labeled. Explore the Excel menus
until you find the word "Hide". Or, press F1 for the Help system and search
for the word "Hide".
Yes there is, on the top toolbar, Format > Sheet > Hide. If you want to
prevent users unhiding them, password protect the workbook.
Note that Excel protection is weak and easily overcome by an experienced
user who has the will to do so,
Regards,
Alan.