Order history for an online garden supply shop

A garden supply shop sells about 4,000 products online and takes about 1,500 orders a day. Customers can open any past order, going back years, and download its invoice again. An old order must show exactly what the customer bought and paid.

Staff edit products all the time. They rename them, change prices and photos, and remove products they no longer sell. Sales tax rates change about once a year and differ by product category. Each order page has a Buy again button that puts the same items in the cart.

What do you store when an order is placed, and what does an order page read years later?