pre ordered iphones are delivered after how many days, does it take more time?

As you progress through the pre-order process, you will see an estimated delivery date.

You must first choose the color, capacity, cellular carrier, payment method, etc.

Once you see the date, there is plenty of time to cancel the order before the process completes.

adding to what sberman correctly provided, once your phone ships, you will receive tracking information to know the exact date it will be delivered to you.