The University of Pennsylvania’s acceptance rate is around 9%, which means they are extremely selective and competitive with their admission criteria.
Your GPA should be at least the average of those accepted - 3.88. Your SAT/ACT scores should be at least the average scores of 1500/32, respectively.
You will have to include 1 letter from a counselor, and 2 letters of recommendation, with at least one in the area you wish to pursue if you know that already.
You will also have to write an essay.
You will have to include official transcripts. You might consider a non-academic letter of recommendation from a community service supervisor.
Early Decision application will likely increase your chances. I hope this helps. Good luck!