Shopify: How to edit the HTML / Liquid on the checkout page?

Question

I just started a shopify store and I want to edit the HTML or Liquid on the checkout page when someone presses "Proceed to Checkout". However, I don't see any template for that in my template editor. Where is this view file?

It looks like it's being redirect to something shopify hosts. The domain changes from myshop.shopify.com to something like https://checkout.shopify.com/carts/47974257/18b0c50ab2bce29f0000e137987g05c8c

Can someone help???

Answer 1

See here: is it possible to create a checkout template?

You can only customize your checkout by editing the checkouts CSS. Shopify must control the majority of your checkout in order to ensure PCI level 1 compliance to protect both you and your customers from potential unscrupulous behaviour on the checkout.shopify.com server.

See here to edit the checkout CSS: Customizing your checkout CSS
Update: For Shopify Plus, see checkout.liquid and checkout.scss.liquid. Otherwise, see here:

If you're on a non-plus subscription, you can customize your checkout in the theme editor by clicking Customize checkout on the Checkout page of your Shopify admin.

There is also the Additional Content & Scripts area in Settings.

Answer 2

Shopify completely explains how you can override the CSS presented in the checkout on their domain so that it matches your theme. You cannot alter any HTML or Javascript. You can however alter the final step of checkout, the Thank You page.

If you are Shopify Plus member, you can totally mess with checkout as they give you access to checkout.liquid