If Tacey's block, "Make changes to your order", does not appear for your customers, one of a handful of things is missing. Nothing shows an error when this happens, so work through this list in order.

This is the most common cause by far. Installing Tacey does not put it on any page. You add Tacey's blocks yourself in Shopify's checkout and accounts editor, once for the Thank you page and once for the Order status page.

Open the editor (Open the checkout editor on your Tacey dashboard, or Settings > Checkout > Edit in Shopify), click Apps, and check the Added count for Tacey. If it reads 0, follow How do I add Tacey to my Shopify Thank you and Order status pages?.

Remember that each page is separate. Tacey can be on the Thank you page and missing from Order status, or the other way round.

In Tacey, go to Editing Tools > Global settings and check Let customers edit their own order is on. It is off until you turn it on.

When it is off, Tacey's own preview says: "Order editing is switched off, so your block does not appear at all."

Go to Editing Tools. If no tool is on, there is nothing to show. The preview says: "No tools are on, so your customers see nothing here yet."

If a tool is on but shows under Needs your attention, it is "Switched on, but missing something a customer needs." Click Finish setup to see what is missing.

Customers can only make changes for the time you set as your edit window, counted from when the order was placed. After that, the customer sees: "The time to make changes to this order has passed. Reply to your order confirmation email if you still need a change."

Check How long the window stays open in Editing Tools > Global settings.

Some orders cannot be edited online, and Tacey says so rather than guessing. For example:

The setup checklist on your Tacey dashboard shows Confirmed under Add Tacey to your checkout and order status page the first time a customer views an order with Tacey on it. If that says "Not yet confirmed", no customer has seen Tacey's block yet.