hi friends do you know  in hyphen and underscore  which is the best one in on-page

You should use a hyphen for your SEO URLs. Google treats a hyphen as a word separator, but does not treat an underscore that way. SEO URLs should use hyphens to separate words. Do not use underscores, do not try to use spaces, and do not smash all the words together into one bigword.

Obviously you should use hyphens not underscores in your site URLs. Because Google hates all the words in url which is use by pressing shift keys like _,&,%.....