You can pursue any degre drom recognised University but must be 21years of age minimum and should be atleast in final year graduation to apear for IAS entrance exam called as UPsC CSE.

You can choose BA Honors as course which is very relevant for IaS preparation  

Students have to clear UPsC CSE Mains, Prelins exams and then have to appear for interview and finally rank list is prepared for all IAS OFficers.