I am a documented American Indian with my certification of degree of Indian blood. Will this be a significant factor in getting accepted by schools?
Yes, being Native American is a significant hook that should increase your chances of getting accepted.
Yes, so long as you have grades and scores to accompany your application. By way of example, if you look at general admission stats for Yale, it’s about 6% admitted. However, for native applicants it is close to 21-22%. Obviously, there is a bit of self-selection occurring, but it is a serious hook.