I just graduated from high school and haven't received the admission notice from colleges and universities. Can I apply for a tourist visa to the United States?

You can apply for a visa. You should call the embassy in advance to make an appointment. When you arrive at the embassy, someone will guide you to apply for a visa. Basically, it will be done in an hour or two, and you will be issued a passport in a week. But now is the busy period for visas. Many international students apply for visas at this time, so I don't know if I can make an appointment until July.