How can I make a script to ban rpb;px players with a gui only from a server?

How can I make it where I click a gui button and it bans a specific user. Just from the server not the whole game.

First off this is not a request site. You cannot expect someone to write out a whole script when you have put little effort in to achieve this goal. You question is a request. If you have a script you should post that so we can take a look. If you have put in the effort but still something is not working then we can definitely help you out. Here is the page on how to post a good question.