Step 1: You need to be able to target a specific page with CSS. Go to your theme.liquid file and find the <body> tag
Step 2: Add this code to the body tag
id="{{ page_title | handle }}"
So that your body tag looks like this:
<body id="{{ page_title | handle }}" >
Step 3: Then before the end of the body tag in theme.liquid add this code:
<style>
#quiz .header-wrapper{
display: none !important;
}
#quiz .footer{
display: none !important;
}
Replace #quiz with the title of your page. So if your page is titled Landing page, it would be #Landing-Page
Step 4: Click save and check how the page looks.