Menu Settings - Off Canvas Menu

The off canvas menu is a special menu area that you can populate with various widgets. 

You can turn the off canvas menu on or off by going to Appearance > Customize > Menus > Juliet Menu Settings. 

If you turn this off, the little “hamburger” menu (the three lines on the top left) will no longer show up for the user to click on and reveal the side page or off canvas menu.