What are the differences between F1 and J1 visa. A lot, but who cares! All you need to care about is that F1 is what you need for being a student. J1 is for scholars (exchanged visitors), e.g. for post-doctoral positions. In conclusion, F1 is what you need to know.
Don’t worry about the visa, at least not until you are offered admission. The school will send you everything you need (i.e. an I-20 form). Fill this form and provide the appropriate documents (the school will tell you all you need to know) to the US embassy. Bring money (to pay for the visa). You are done!
Exception will be for those that require proof of financial means. This is if you don’t have financial aid from the school, i.e. no letter of financial aid that covers the tuition and the living expenses. Then it means: problem. You need to show that have the money for the duration of study, which is logical. So, check your bank account, or of somebody who is willing to issue a warranty for your expenses.