My wife worked in cdib for the Choctaws. Each tribe will have a department dedicated to issuing indian id cards. They will need your social security number and a birth certificate. The more family tree info u have the better. A lot of indian bloods would not put on birth certificates when a child was born to prevent any unfair treatment. They would hide it. You'll need to go back far enough in your tree where they had it on their birth certificate. Also, you'll need to know the tribe. Get the info, then start checking indian tribe web sites.