Checkout page can be modified if you have Shopify plus account. As per your image seems like you have selected that product so it is showing. You can check at the cart page and remove it.
Hi there @queenann!
Don here from Shopify.
It looks like this is the Customise theme menu in your admin, from where you can customise the appearance of your store's theme.
It also looks there like you have added an item to your cart in this store preview, so we can now see it showing up in your checkout.
As @MS-WEB-DESIGNER pointed out, you can navigate to the cart page from there in order to remove this product if you don't intend to have it there.
If you can share a link to your store with us here, I can show you how to do so.
Would you still be working on building out your store before launch, or have you started selling there already?
Hi again @queenann!
Don from Shopify once again.
Could you share a link to your storefront with me here so I can take a look at this with you?
Would this behaviour be happening on your store itself, or do you just see this in the Customize theme menu?
The more you can let us know about what's happening here the better we'll be able to work together on this.