Shopify Plus stores have access to a special file called "checkout.liquid", which enables them to add tracking codes to their checkout pages (such as payment, delivery, etc.) and monitor user behavior. In this article, we explained how to enable the checkout.liquid file for Plus stores to enjoy.
Let's get started!
Step 1: Head to your Shopify Admin page > "Online Store" > "Themes". Then, on your current theme, click "Actions" > "Edit code".

Step 2: In the "Layout" section, click "Add a new layout". Here, choose "checkout" from the dropdown menu, and click "Create layout".
(PS. If you can't see the "checkout" option in the dropdown menu even though you are a Shopify Plus owner, please get in touch with your Shopify Representative to enable the feature for you.)

And we are already done! Enjoy your checkout tracking :)