Yes, if you come from the United States, you are American. This is because the term "American" refers to a person who is from the United States of America. It can also refer to a person who is a citizen of the United States, even if they were not born there.
There are two ways to become an American citizen: by birth or by naturalization. People who are born in the United States are considered American citizens by birth. People who are born outside of the United States can become American citizens by naturalization, which is a process of meeting certain requirements and taking an oath of allegiance to the United States.
The term "American" can also be used to describe the culture and values of the United States. These include things like democracy, freedom, and equality.
So, if you come from the United States, you are American. This means that you are a citizen of the United States, and you are also a part of American culture.