How to become IAS officer?

Indian Administrative Service (IAS):

To become IAS officer you need to pass UPSC Civil Service Exam.
The UPSC Civil Service Exam consists of 3 stages and they are Preliminary Exam, Mains Exam, and Personality Test/Interview.

UPSC Exam details:

The competitive examination comprises two successive stages:
I. Civil Services (Preliminary) Examinations (Objective Type) for the selection of candidates for Main Examination; and
II. Civil Services (Main) Examination

For details click https://eloksevaonline.com/competitive-exams/civil-services-examination-pattern/.

Nationality:
For the Indian Administrative Service (IAS) a candidate must be a citizen of India.

Age & Attempts:
a. Minimum 21 years of age (as on 1st August of the year of examination).
b. The prescribed upper age limit is based on the various categories that a candidate belongs to:
General Category: Maximum age – 32 years/6 attempts
OBC: 35 years/9 attempts
SC/ST: 37 years/ No limitation on number of attempts.
Physically Disabled (Blind, Deaf, Orthopedic): 42 years
General Category: 9 attempts
OBC: 9 attempts
SC/ST: Up to age limit
J & K Domicile:
General Category: 37 years
OBC: 40 years
SC/ST: 42 years
PH: 50 years

Academic Eligibility for Civil Services IAS Exams:
The candidate must hold a degree of any University that is recognized by the state or central government.
A degree received through Correspondence Education or Distance Education.
A degree from an Open University.
A qualification recognized by the Government of India as being equivalent to either of the above.
Candidates who have given their final year graduation exam/ waiting for the results can also apply for this exam (but they will be required to produce proof of passing the graduation exam) before the final selection process.

UPSC Online Application Procedure:
The application procedure for UPSC civil services examination has been entirely made online at the preliminary level and UPSC e-admit cards are issued which candidates appearing for IAS exam should download from the UPSC official website.

Click here for more details.

District Collector/District magistrate:
A directly recruited IAS officer undergoes training for the first 2 years. After that, (s)he is posted as a sub-divisional officer in charge of a revenue subdivision[1] in a district. After spending 2-3 years here, (s)he gets posted as an Additional District Magistrate(ADM) to get acquaintance of developmental administration. After this only, (s)he can hope to be posted as a DC in a district, and that too in a comparatively easier and smaller district.