In any case, the college you enroll through is your home college. Contact your home institution's bookstore online, by email, or by phone. Purchases require payment by check or credit card before materials will be sent. If your plans include taking a math or English course, you may be required to take an academic skills assessment test prior to placement in your courses. These tests are usually arranged by on-campus admissions staff.
Some instructors give tests online.
Others may have tests proctored in a testing room or a testing center at your home institution or another location approved by your instructor. That information will be found on the instructors class page. My instructor wants me to take proctored tests. Each instructor is free to determine the value or need for testing in a proctored setting. If you are required to take a proctored test, go to your home school, or arrange for the test to be taken at another suitable site.