There's no pretty way to do it.
But if you go to Applied Effects and open up the Motion effects, you'll be able to adjust Scale so that the clip fills the frame.
You'll likely lose some of the top or bottom of the clip in order to fill it side to side and you're also up-rezzing, so your clip is going to look kind of blurry. But that's how it's done anyway.
Thanks for posting in Adobe forums.
I understand you are facing issue in rotating a frame in Adobe Premiere Elements.
Please check & follow this article for reference.