College admissions tests are hard! No matter how well you prepared for them the first time, you may not have gotten the score you wanted on your first try. Many people retake the tests at least once in order to learn from their mistakes and improve their scores.
It's definitely a good idea to take either test up to 3 times- a higher standardized test score can play a fairly big role in your college admissions results, so don't feel like you have to accept the first score you get. On the other hand, everyone has their own limitations, so there's no point in taking the tests over and over again if your scores are not significantly improving.
Once you've taken the test a few times and gotten a score that you're happy with, you might be wondering what to do about reporting that college admissions test score. Both the ACT and SAT allow students to choose which scores are reported, so no university will have to see a score that you don't want them to see.
However, both tests also offer students the ability to choose a few universities to automatically send test scores to while they are taking the test. Think carefully about whether you want to do this before you go into the test, because you can't un-send the scores once you have filled out that option on the test. If you automatically send your scores each time you take the test, then your colleges of choice will see every score you receive. Sending later will cost you more, but it will also give you more control.
If you do hold off on sending your scores, you will be faced with a choice: should you only send in your best scores, or should you choose to send more? Naturally, you want any college that you are applying to to see the highest test scores you received. But depending on your other application materials, it may actually be in your best interests to send in a lower score as well.
Sending in an early test score and a later, better score shows colleges that you care a lot about college admissions and will work to improve yourself. There are situations in which it can be beneficial to send this message, especially if your high school grades are not as good as they could be. Demonstrating to colleges that you have taken multiple standardized tests and improved your score will signal to them that you are planning to take academics more seriously from now on.
If you have a good college counselor or guidance counselor, it might help to discuss this decision with them. And regardless, remember that your test scores are only one part of your college application-- your admission will depend on the full portrait that you paint of yourself!