The IAS Exam is conducted by UPSC named as Civil Service Exam.

The Civil Service Exam will be held in 2 Part:
Preliminary Exam
Main Exam

Here I am providing syllabus of UPSC Civil Service Preliminary Exam for your reference:

UPSC CIVIL SERVICE PRELIMINARY EXAM SYLLABUS

Paper 1 - General Studies:
Current events of national and international importance.
History of India and Indian National Movement.
General issues on Environmental Ecology, Bio-diversity and Climate Change
General Science
Indian and World Geography - Physical, Social, Economic Geography of India and the World.
Economic and Social Development - Sustainable Development, Poverty, Inclusion, Demographics, Social Sector initiatives, etc.
Indian Polity and Governance - Constitution, Political System, Panchayati Raj, Public Policy, Rights Issues, etc.

Paper II Aptitude Test:
Comprehension
Interpersonal skills including communication skills;
General mental ability
Logical reasoning and analytical ability
Decision-making and problemsolving
Basic numeracy (numbers and their relations, orders of magnitude, etc.) (Class X level), Data interpretation (charts, graphs, tables, data sufficiency etc. - Class X level)

Exam Scheme:
Paper - I General Studies 200 Marks Two Hours
Paper- II (CSAT) Aptitude test (CSAT) 200 Marks Two Hours