Buying new phone

It will deduct from the total price of the device after taxes have been applied, and then calculate your monthly payments based of off that new price.

So if the iPhone 12 you choose is $999, then add taxes ends up at $1100 then the value of the iPhone 8 will be subtracted from that total. So you end up with $949 for example then that $949 is what gets distributed into the financed monthly payments.

It depends on how you purchase your new phone. If you buy in an Apple store you can trade in your phone on the spot. If you can't buy from an Apple store directly, you order your new phone, identify the trade at the time of order and once you've received your new phone, you'll receive a box with instructions how to send the phone back in. Once the phone has been received and evaluated by Apple's partner, if there is a disparity in the condition you identified, they can tell you the phone is worth less than what you were expecting and you either accept the reduction of ask for the phone to be returned to you.