To become an IAS officer you need to clear UPSC civil services examination.
To be eligible for UPSC examination you need to be a graduate , there's no need to be a graduate in a particular discipline, all you need to be is a graduate in any discipline from a recognised university be it mbbs B. Arch, Btech, BSc or any other course.
You can check UPSC eligibility criteria below
* You must have a bachelor's degree in any discipline from a recognised university
*Minimum age limit :- you need to be at least 21 years old to be eligible
*Maximum age limit :- 32 years , also there's 3 year relaxation on upper age limit for obc and of 5 years for sc/st category
For detailed information go through