I applied in-person. The process took 6 months. I interviewed at US Army (Fort Lewis, WA) in Aug 2019
Interview
Get in touch with an army recruiter to discuss your interest in joining. They will guide you through the application process and provide you with detailed information. You can usually find contact details for recruiters on the official website of the army branch you want to join.
None, you take a PT test and a few other technical skills, but no real interview to speak of (unless you apply for a specialized role beyond the basic entry roles people typically have)
Study the Military Flight Aptitude Test. Practice taking the test multiple times. Get letters of recommendation from actual US Army pilots. Get a high score on your physical fitness test.