Hide complete menue on specific posts

Hello,

1. You have to customize the theme to achieve that. You have to use post id for each page to hide the menu using custom css.

ex:
.postid-273 div#navbar {
display: none;
}

Or you can hire to team to customize the theme for you.

2. Goto Customize > Single post settings > Single Post Layout Style > Single Post Style 1

to hide that section.

Thanks