How i know 100% that i hit puberty my age is 16 ?

The first reliable sign of male puberty is testis enlargement. Growing from peanut size (~1cm+) to large olive size ((~5+cm).

There is no way to know anything in medicine 100% in individual patient. Well, I could probably tell a100% if you were dead. The Tanner x-ray bone age is the standard. But also a problem is what do you mean by puberty? Whiskers, body hair, erections are a good way to get an idea. Voice changed? stopped growing taller? Ask ur local Dr who has more experience than I seeing Indian boys like you