Test Optional means that it is not mandatory for students to submit their SAT or ACT scores as part of their college application. However, they will consider SAT and ACT scores if they are submitted.
If you decide not to submit your test scores, the rest of your application, such as your grades, essays, extracurricular activities, and achievements, must be strong enough to be admitted. Remember, you are competing against students that may have opted to submit their test scores.
Consider why you would not want to submit your test scores. Being a test optional college does not mean that the college has relaxed its admission standards. Also, test optional policies differ from college to college.
If you have strong test scores that are at or above the 50th percentile for the college you are applying to, and a strong application, you might consider submitting your scores. However, if you do not have strong test scores, but the rest of your application is stellar you may consider not submitting your scores. If you do not submit your scores colleges will place more emphasis on the rest of your application.
Remember, colleges want to assess the best of you, be that with or without your test scores.