Boyfriend is studying in America. Is it better to apply for a tourist visa or a visiting visa to visit him?

From the perspective of immigration law, you have nothing to do with your boyfriend, so you can't apply for visiting relatives.

You can apply for a tour, but whether you can approve it depends mainly on personal and family conditions.

For example, which city do you live in, your parents' work situation, what university do you go to, your past experience abroad and so on.

Generally speaking, the chances of a girl your age refusing a visa are much higher than the chances of success.

In addition, you can't mention your boyfriend, which will greatly increase your chances of being refused a visa.