hey guys, i was wondering if it is possible to edit the contents in a iframe to match your sites needs, like for example css/html. Is there any way this can be done in javascript or regular html?

No, the content of the iframe is generally stolen from an external site so has that site's scripts and css and copyright notice
contact the other site owner to request a copy of the content to include in your site with appropriate attribution,
or write your own content

all site owners should place framebreaker scripts in their menu include to prevent such theft