To use Amazon's new feature, look for the Amazon Day option at check out on your next purchase. Once it appears, you can select what day of the week you want all of your goods to arrive. Instead of shipping a product as soon as you check out, Amazon will stack up all of the orders that you want to be delivered on your designated day and bring them to your door in a single trip.
Your future orders will only be delivered on Amazon Day if you choose that option, otherwise, you can have packages shipped the normal way if you can't wait. You'll also typically have to wait at least two days from when you place your order for your goods to arrive, so don't try to game the system by setting your Amazon Day as Friday and then filling up your cart Thursday. Most good eligible for Prime two-day shipping will be eligible to ship on Amazon Day.
Amazon began testing this feature late last year on an invite-only basis but has now opened up the Amazon Day feature to all Prime members. The initiative appears to be part of Amazon's attempt to shrink its environmental impact. The company intends to make half of its deliveries carbon neutral by 2030.