How to show menu in wordpress plugin page

I have created a wordpress plugin named test. In this i have created a test.php which is plugin file and a another file test2.php. In test.php i have created a hyperlink and on click on this link i am sending data to another page test2.php. When I am click on this data is shown in url. How can i hide this from url. And in test2.php i need to call theme header and menu's. I am using get_header function in test2.php but it say undefined function. How can i show header and menu's on test2.php.

via Chebli Mohamed