Hello Dear Student,
After completing your Graduation with minimum 50% aggregate marks (for general), you will be eligible for appearing in UPSC CSE (Civil Services Examination). In UPSC CSE Exam if you will Secure Top Rank (after clearing all the stages of examination I.e Prelims, Mains and Interview) then you can secure post of IAS officer.
And After Selection your Training for the Post of IAS Officer will begin at Lal Bahadur Shastri National Academy of Administration, Mussoorie, Uttarakhand.
All the Best