Is it possible to buy iphone with the bitcoin ?
Yes, you can buy an iPhone with bitcoin, but you can directly buy it in an Apple Store. You will need to find someone who is selling an iPhone here or over the internet that is will to accept bitcoin as payment.
Is apple accepting bitcoin in future for the purchase of Iphone?
As of now, Apple is not accepting bitcoin or any other crypto as a way to purchase their products. You can try here
openbazaar.org I think you can find an iPhone there.