If so, could anyone give an example pls?
It is almost never appropriate to use it for a person. Sometimes, we seem to use it when asking about somebody's gender. E.g.:
but here it is just a dummy pronoun.
If you don't know the gender, you have the following options:
Note that it is very offensive to refer to transexuals, transvestites, hermaphrodites, and so on as it. If the person adopts a male name, use he. If the person adopts a female name, use she.
Usually "it" refers to an object. A person is usually referred to by "he", "she", "him", "her", etc. A gender neutral way is to use "they" or "them, even for singles.
"John is dirty, it hasn't taken a bath in days."
"John is dirty, he hasn't taken a bath in days."