There are dedicated post-baccalaureate programs for non pre-meds interested in attending medical school. These career-changer post baccs are 2 year long highly structure programs that offer all the typical pre-med class requirements as well as opportunities to get involved in clinical volunteering and lab research. Some include MCAT prep either as an extra or as part of the program.
A few of these post-bacc programs have linkages–which guarantees a post-bacc student who hits certain GPA and MCAT thresholds an early decision interview with an associated medical school.
These formal programs tend to expensive and there is little or no FA available.
It’s also quite possible to do an informal post-bacc independently by taking the necessary pre-reqs piecemeal at any 4 year college as non degree-seeking student & developing appropriate ECs before applying to medical school.