Hello aspirant,

You can study Bachelor's degree in any stream or any other specialization because minimum Undergraduation degree from a recognised College or University, is required for being eligible for UPSC exam.

Best Specializations in Arts stream which are useful for UPSC exams are listed below.

Political Science

Humanities

History

Psychology

Public Administration

Economics

Geography

Philosophy

Literature

Best B.E/ B.Tech Specializations are given below.

Computer Science Engineering

Mechanical Engineering

Electronics and Communication Engineering

Information Technology

Civil Engineering

Electrical Engineering

While you are in Graduation take coaching for UPSE or can prepare yourself

After completion of Graduation you need to appear for UPSE CSE exam. Exam is conducted in three stages.

-Prelims

-Mains

-Personal Interview

You have to qualify all three stages with good score and also Medical fitness test too. Based on your performance in exams you'll be given posts like IAS, IPS, IFS, etc.

To know how to prepare for UPSC IAS go through below mentioned link.

https://competition.careers360.com/articles/how-prepare-for-upsc-ias

Know how to become IAS officer check below mentioned link.

https://www.careers360.com/keywords/ias-officer-career

To get more information go through below mentioned link.

https://competition.careers360.com/articles/upsc-ias-eligibility-criteria

I hope this information was helpful to you.

Good Luck!!