URL Rewrite: how to

[Pocket_Sevens]

Warning:  noob question here so I appreciate your patience, and I apologize if this is in the wrong forum.

I have a few cases where I want to automatically append some text to a URL when a user enters a URL in a browser.  E.g. when a user enters www.duckduckgo.com, I want the text "&kp=-1" to be appended to the url. 

Not being familiar with URL rewrites, could someone point me in the right direction?

Thanks.