I purchased iphone 6 used from friend now he is not reachable and when i restored the device on itunes it's asking for previous apple id and password i don't have any details even i made new account it's not accepting kindly give me a solution

There is no solution to this and you have come across activation lock which you can do nothing about.

If you cannot contact the previous owner of the phone to ask him to remove his details, then there is nothing you can do. You CAN NEVER use this phone.

Apple will not help you and if this has happened there is a good chance that the phone might be stollen.

Try and return the phone and get your money back. You have learned a lesson the hard way and you can never use this phone.

Start again and buy another phone from a legitimate source that you can use, because with this phone you have a useless brick that you can never use.

Some "friend". You bought a paper weight.