You didn't provide any info regarding year, make, and model of the trailer. It might matter whether the trailer is fairly new and whether the manufacturer is still in business whether it should go to an authorized dealer or any independent RV repair shop.
Sometimes the wheel skirts are molded plastic or fiberglass pieces unique to your trailer and difficult to obtain from sources other than the trailer manufacturer.
Any good RV dealer service department can probably perform fiberglass repair work if side panels were damaged but if the skirt was destroyed that can make the repair more challenging due to repair parts needed.