You must have your currently valid passport from your country of citizenship, your student visa issued by the US consulate nearest your home in your country (which should be in your passport), and your I-20 form issued by the university where you are enrolled. You are allowed to enter US up to 30 days prior to start of classes (so you can attend orientation, class registration, etc.).
When you say "valid 2020 July," do you mean valid UNTIL July of next year? To return to school for the 2019-2020 school year, you must prove you are still currently enrolled at that university for the coming year with your I-20 form. No legitimate student visas have been issued yet for the 2020-21 school year, so a start date of July 2020 does not appear to be possible.
Upon entry to US, immigration checks your biometrics AND verifies that you are actually enrolled at the school for the coming term.