Do I need to go to the embassy to apply for a visa to travel to the United States with a group?

You don't have to handle it all yourself, but you must go to the interview yourself. If you join a tour group, the travel agency should have a visa agency business. You can ask them to do it. I traveled to the United States with a group from all directions, and I also asked them to help me. I sent an invitation letter when I left with their group, which seems to be helpful for visa application.