Some colleges may require that you take one or more standardized tests for admission. That depends on the college's policy. It is important to remember that test scores are a part of the total applicant profile, and at most institutions test scores alone do not exclude you from admission, nor do scores alone guarantee admission. Recently, some colleges have changed or eliminated the standardized test requirements as part of the admissions process so be sure to check the policy of the colleges you are applying to before you take the test.
The two most common test programs are the SAT Reasoning Test and the American College Testing Program (ACT). Also available is the Preliminary Scholastic Assessment Test (PSAT). Here is the site to register for the SAT: Collegeboard.org. Here is the site to register for the ACT: ACT.org.
It is your responsibility to register for all tests and arrange for the results to be sent to the institution of your choice. It is recommended that you register for at least the following tests:
Fall of 10th and 11th grade- PSAT
Spring of 11th grade- SAT or ACT
Fall of 12th grade- SAT or ACT
If you elect or are required to participate in the ACT program for admissions you should arrange to take the test in the spring of your junior year or fall of your senior year.
SAT Subject tests should be taken as required by the college or university.