Hello Aspirant,

Once you complete your 10+2 with PCM/MPC background there are lots of option available for you other than engineering. Like you can become an architect, a naval officer, a commercial pilot and many more career options. 

Let us discuss the options in detail :-

@ARCHITECT  
It is the study of designing and building beautiful structures. B.Arch is the course required for this profession.
Some entrance exams are NATA, JEE-Main paper 2.
Some recruiters of this field are :- 
Gensler, IDEO, Frog Design, IKEA, Sanjay Puri Architects, Abin Design studio etc.

@COMMERCIAL PILOT  
Here you can be a tour pilot, cargo pilot or even an airline pilot. There are some entrance tests for PPL and CPL courses
Some recruiters of this field are :- 
Air India, Air India Charters Ltd, IndiGo, Spice Jet etc.

For complete details about all other careers options kindly check out the link given below :-
https://www.careers360.com/careers/articles/career-options-after-12th-science-pcm-counar


I hope this information helps you.
Good Luck!!