Show an order confirmation page
If your store's legal business address is located in any region governed by European Union legislation, you might need to give your customers the opportunity to confirm their order before completing checkout.
You can display the order confirmation page by activating checkout confirmation in your Checkout settings:
From your Shopify admin, click Settings, then click Checkout.
Find the Order processing section and select the Require a confirmation step checkbox.
What your customers see at checkout
When Checkout confirmation is enabled, your customers will experience a three-page checkout. The final page gives them the opportunity to review their order before confirming it.
They can click on any of the Edit buttons on this third screen to go back to the relevant page and change the details.
When they're happy to proceed with the order, they must click Complete my purchase to confirm. Otherwise, they can click cancel, and return to store to abandon checkout.