If you’ve added a custom background image using the Custom Background page under your Appearance menu or from your customizer, it will display on every page of your site.
The code for this is located in your child themes functions file:
//* Add support for custom background
add_theme_support( 'custom-background' );
What if you want to remove it from your home page, landing page or any other pages?
There’s 2 ways to do this:
Add To Template File
You can add this tag directly in a template file like your front-page.php, home.php or page_landing.php file: