How can i edit the "category" page

I've been trying to mess around with wordpress but my knowledge is really vague. I want to place some kind of button next to the Category title. Highlited here : http://i.imgur.com/d46lJll.png

Now once i can find where to place some text/button next to the Category Title it must have add some url parameter and refresh the page. Like this:
* Visitor is on this category page: http://insurancebros.net/category/auto-insurance/
* Visitor clicks on that button added. And then he should be redirected to this url :
http://insurancebros.net/category/auto-insurance/?something_here

I've tried to edit "single.php" and "archives.php" but seems it's not one of them. Any ideas guys?