To start with Engineering you must choose science stream after Class 10th board examination with subject combination of Physics, Chemistry and Maths (PCM).
After Class 12th boards, you need to sit for engineering entrance examinations including JEE-Main, JEE-Advanced, GATE, BITSAT, etc.
To initiate a career in Medical you must choose science stream after Class 10th board examination with the subject combination of Physics, Chemistry and Biology (PCB).
Further after Class 12th boards, you need to appear for medical entrance examinations including NEET, AIIMS, JIPMER, etc. to pursue MBBS thereafter.