Each branch of the U.S. Armed Forces is responsible for its own recruiting. You can learn more about each branch's recruiting policies, and contact a recruiter directly, at the following websites:
Army: https://www.goarmy.com
National Guard: https://www.nationalguard.com/
Marines: https://www.marines.com/become-a-marine/process-to-join.html
Navy: https://www.navy.com/careers
Air Force and Space Force: https://www.airforce.com/how-to-join
Coast Guard: https://www.uscg.mil/Join/