I am update iPhone 4s 9.3.5 to 9.3.6 and it's completely finished progress bar and it's asking iTunes.. please help me

It would be better if you can please re-post with a screenshot, in order to understand the phenomenon better. Images / pictures speak louder than words. Do not provide any personal credentials, such as email id, apple id, IMEI number, Serial Number, Phone number, Order ID, if you are sharing a map ensure your location is not identifiable. Etc.