Ren here from the Shopify support team, happy to help shed some light on this for you.
In consideration of security and privacy, the checkout page is not currently an editable feature on our standard Shopify plans. This is in place to protect the tools that enable us to take customer info and payment safely. Our checkout is built in a way that allows us to safely secure this information and any customizations may compromise that security.
You can however make some general modifications to the cart page as well as perform changes to the language on the checkout page by going to Online Store > Actions > Edit Languages > Checkout.
Checkout liquid access is reserved for Shopify Plus accounts. If you are interested in a Plus account or learning more, you can request a consultation at this link. You will get in touch with a consultant that will map our your store requirements, explain the Plus platform capabilities and identify your opportunities for growth and expansion.
Let me know if I can clarify any of the above for you!
@Ren7Your response indicates that the language on the Checkout page can be changed. However, that functionality appears to have been removed, as all the language in the Checkout section of Languages has been grayed out. While I understand the need to secure the functionality of the checkout page as you've explained, the language connected to the Email Marketing opt-in is a feature that I've found MANY Shopify clients would like to edit (this seems to come up quite frequently in the community). Is modifying this language possible? If not, I HIGHLY recommend that Shopify consider changing this. Thank you.
This is Ren from the Shopify support team, here to help you out.
Are you referring to the greyed out labels here?
They are in fact changeable, you simply need to click and alter the text to say whatever you'd like. In this example, I've changed the wording to say "Yes, send me occasional promos and news" and you can see that reflected on the checkout page here:
If the changes aren't taking effect for you, I would encourage you to attempt from a different browser and see if that resolves the issue. Let me know how that goes!