How can I remove text widget box (or center my ad)

https://i.imgur.com/sS0cbyp.png – Image

As you can see, I have an ad on my website, but it looks very bad because when I put the code (iframe code) into the text widget in wordpress, it looks un alligned (The ad itseld has a border box, which is what is causing the issue).

Trying to change the ad’s width/height starts to cut the ad which is not what I want. How can I either get rid of the text widget border completely, or at the very least – reallign it to fit perfectly in the widget box (ie: move a little to the left and cut the border below?).

If this is possible please let me know what I can do. Thanks!