how to became a soldier?

A soldier requires you to have a lot of criteria's to fulfill.

Now in the eventuality you are ready to get into it. Then during class X you can write an examination called National Defence Academy Examination or simply said as the NDA examination. If you miss out on this, you can apply again after class XII examination.

PFB Eligibility Criteria (As obtained from official recruitment website of the Indian Army)

Age between: As per UPSC notification

Qualification: 12th Class of 10+2 System of Education/Equivalent for Army and with Physics and Maths for AF & Navy

Marital Status: Unmarried

Application to be Received by: As per UPSC notification

Likely SSB Date: Sep to Oct and Jan to Apr

Date Commencement of Training: Jan and Jul

Training Academy: NDA, Khadakwasla, Pune

Duration of Training:

3 Yrs at NDA and 1 Yr at Indian Military Academy (For Army cadets)/

3 Yrs at NDA and 1 Yr at Naval Academy(For Naval cadets)/

3 Yrs at NDA and 1 & 1/2 Yrs at Air Force Academy, Hyderabad (For Air Force cadets)

Please refer the links:
NDA
Army
Navy
Air Force

For the NDA exam Results please check: UPSC
There was a paper that used to come Employment News. When I had applied for NDA it was because of the advertisement on this paper. Check if you can subscribe for the paper. Or Click Here.

Finally, All the very best. May you shine in the Defence sector of India.