Hi Swarnabha,

I this your talking about veterinary doctor. If so then here is some information about it : 

Step 1: Earn a Bachelor's Degree

Prospective veterinarians generally need bachelor's degrees to qualify for admission to a veterinary college. While there isn't one specific major required, students need to take a minimum number of science courses during undergraduate school, such as in chemistry, biology and physics.

Step 2: Take the GRE

Veterinary colleges typically require that DVM program applicants take the Graduate Record Examination (GRE) and submit their scores to the admissions office. The GRE tests an individual's verbal, quantitative and analytical skills.

Step 3: Complete a Doctorate of Veterinary Medicine Program

A DVM program takes four years to complete and is composed of three years of pre-clinical instruction and a final year of clinical training.

Step 4: After this you have to obtain license.

Hope this will help you.