Remove Apple ID and passcode

Contact Apple ID Support. Apple Support will need to see the original purchase receipt with the serial number/paperwork.

Apple ID - Official Apple Support.    

Contact Apple for help with Apple ID account security - Apple Support.  (Link doesn’t always load)   

Get Support      Work through the screens to get a chat option. 

https://twitter.com/AppleSupport

See the article https://support.apple.com/en-in/HT201441

You bought refurbished iPhone , even you show receipt to the apple support ( the first owner has to call them as their Apple ID account is registered with them and all the data of that person ) .