Hi
For this you have to join aviation courses by giving entrance exams. There are three main entrance exams - Indira Gandhi rashtriya udan academy test , air force common admission test, aircraft maintenance engineering common entrance exam.
The main objective of all these entrance exams is to evaluate the reasoning skills, general knowledge, communication skills and decision-making skills of the candidate. For preparation you can join coaching classes or you can do self study also according to the syllabus.
Hope it helps....