Ash here from the Shopify team. Welcome to the Shopify Community!
Thank you for posting your question, and I'm happy to help look into where this "Check if Ship to your Zip Code" box is coming from. In order to assist, I'll need to get a bit more information from you. Could you please reply back here and send me a link to your site so I can take a look on my end? Also, could you please send me a screenshot of the check box so I know what to look for and where to find it?
Looking forward to helping out!