Store settings has a new Checkout band. Choose a published Store page under Terms at checkout, and the Checkout page will show a required box agreeing to it, linked to the page. Buyers cannot go on to payment without ticking it, and the order page shows when they agreed.
Terms at checkout
A Store can require buyers to agree to one of its pages, such as its terms of sale, before they pay.
How it works: Terms, Newsletter sign-up and reminders at checkout