Hi there. 

First things first, for becoming an IAS officer one has to write the UPSC examinations that occur in three stages: Preliminary, Mains and Personal Interview. 

The Preliminary exams is just for the sake of qualifying to Mains. Your preliminary exam's score won't be considered in the final score. The final score consists of Mains and Personal Interview. Preliminary is an MCQ based exam whereas Mains exam is a full-fledged written exam with an optional subject. 

One needs to have a graduation degree in any discipline from any recognized University to be eligible to write the UPSC examinations. Hence, if you are confused in what to pursue for your graduation degree I'd suggest you to go with a BA degree in History, Geography, and Political science combination. This combination would be the best and would help you a lot in your preparation of UPSC CS.

It is advisable to start your preparation from the very first year of graduation. Start with the basic NCERT books of Class VI-XII of History, Geography, Economics, and Science. 

Slowly, build momentum and start with Indian Polity book by Lakshmikant. For a proper and full booklist head to Mrunal's blog or Unacademy's website (Roman Saini's lessons). 

Develop a habit of reading The Hindu daily to be updated with current affairs. Read the Yojana Magazine regularly. 

For more information on UPSC exams like the syllabus and as such kindly refer to the following link: 

Https://competition.careers360.com/exams/civil-services-examination

Wishing you luck!

Hey!

As per the eligibility criteria of UPSC, any graduate candidates can apply for the exam. In order to qualify the civil services exam, you need to prepare well. For details about UPSC eligibility criteria - Check Here

Hello,

You can pursue any degree. According to the eligibility criteria, any graduate candidates can apply for the exam. To crack the exam prepare well.

Thank you!!

you want to go for civil services and there is no point to choose engineering you could simply choose bachelor of arts with your interest like political science or something and then start preparing for civil services exam choosing behaviour Android you two advantages you don't need to waste time on studying Engineering or other  course and and you would be studying same what will be asked in civil services exam