Shopify Purchases + Studio
Adding custom scripts to your order confirmation page
As these pages are being handled by Shopify, scripts and tracking codes will need to be added via Shopify, not Studio. See Conversion Tracking for Shopify Purchases.
When using Studio with Shopify almost all of your store is managed through Studio. However, there are a couple parts that are not managed through Studio; specifically the checkout process and the order confirmation page in particular.
These are completely handled by Shopify, and changes to them need to be made through Shopify.