There are various courses after 12th standard. Some of them other than engineering are as follows :-

• If you have interest in pure sciences then you can go for BSc in Physics or Chemistry or microbiology or any other subject. 
• If you have interest in medical then you can give entrance exam like NEET to get admission in any of the medical courses available.
• If you have interest in building applications, programming, etc then you can go for BSc IT (Information Technology) or BSc Computer Science. 
• If you have interest in business, finance, economics, etc. then you can go for B. Com (Bachelor of Commerce) or BMS (Bachelor of Management Studies) or other similar courses. 
• If you have interest in geography, history or any other Arts related field then you can go for B.A (Bachelor of Arts) ,etc. 

If you are thinking of writing the exams conducted by UPSC then you can choose graduate course accordingly. Almost for all the exams conducted by UPSC the candidate can be a graduate from any of the field but do check accordingly. 

If you still have any queries feel free to ask in the comment section down below. 

Hello Dear

Since you are interested to do the UPSC after the completion of your Class 12th . See , here you need to understand that if you want to do the UPSC then you can go with the option B.Sc or B.A as an compulsory UG degree and if you can be able to achieve the good score in the JEE mains & by God grace if you get any good government institution then you should opt that respective college & side by side during your graduation you can go with your preparation of UPSC I think that way it will be faar better.

All the best