I am using moodle 3.5 and there is another website that gave me its web services .
How can i customize my moodle quiz result page that can send quiz result to that website via given webservice and show custom messages according to web service?
Generally, you don't do this from the quiz. You send the grades from Moodle's gradebook.
I don't think there are good standards in this area. What does exist is quite a nice export from the gradebook in a Simple XML format. That is a good place to start for building integrations.