Activation lock

I have a another iPhone 6.

Recently I forgot my passcode.later I connected it to iTunes and make a restore.All it's fine.After I setuping activation lock arrived.i don't know what is the exact Apple id and password.How can I fix that.I can't loss that phone. It is my favourite phone.Please fix this to me.Now iam using an another iPhone 6.Is there is any scope to unlock that by using this other iPhones.