What is the requirements for an adopted 16 year old?

Requirements regarding what exactly? As adopted you are a part of their family just as if you are their biological child with the same rights etc and they decide over you just like in any other family until you reach the age of majority in your state, usually 18. If you are adopted at 16 you have the right to consent to the adoption or not. If you want early emancipation the requirements differ slightly from state to state and not all states offer it but the law is the same regardless if you are adopted or not.