On the successful completion of MBBS Course only from AFMC the medical cadets join the Armed Forces  Medical  Services  as  Commissioned  Officers  in  one  of  the  three  services,  viz.  Army,  Navy and Air Force. You can check the further information with the given below link.

http://www.afmc.nic.in/PDFfiles/3511815545AFMC MBBS Information Brrochure 2018.pdf

Good Luck!