Civil Services are mentioned in Indian constitution and are of three types-
1-Central Services- includes those services which are recruited and paid by the central government and they serve for the centre only .Example- Indian Foreign Service,Indian Revenue Service,Indian Engineering Service etc.
2-All India Services-includes those services which are recruited by the central and paid by the State government where they are posted and they serve for the respective States according to their cadre .There are only three All India Services Example- IAS,IPS and Indian Forest Service.
3-Provincial Services or State Services-includes those services which are recruited and paid by the respective States and they serve for the States only . Every state has its own state service.Normally these are known as PCS.Example- UPPCS(UPPSC),MPPCS or RAS(in Rajasthan)
All above exams have more or less similar patterns and syllabii which includes-
1-General Study for Prelims and Mains
2-CSAT for Prelims
3-Optional Subject for Mains
4-Interview after Mains