CSU Admissions

So, I’ve taken the SAT without essay and I was wondering if CSU campuses require you to take SAT subject tests. Also, do I have to send my AP test score to them if I did really bad on it? I’ve went on their website, but they don’t seem to talk much about this.

no CSUs require subject tests.
generally, you don’t need to send in AP test scores if you don’t want to.
Do note that UCs require the essay portion of the SAT.

SAT subject tests are not required for CSU and you do not need to report any AP exam scores (you will need to list the AP classes and the grades you got since that info will be on your transcript).

You can self report all, some or none of your AP test scores and you will only send in your AP score report to the college you eventually attend. As noted by @ProfessorPlum168, if you are only applying to the CSU’s, then essay portion is not necessary. If you however decide to apply to any UC’s or private schools, then the SAT essay will be required for the UC’s and possibly some of the privates.
SAT subject tests are not required by the CSU’s and recommended for some majors at some of the UC’s. SAT subject tests can be used to fulfill an a-g course requirement if you are lacking that requirement.