It’s or its?

It’s is the contracted form of it is or it has:

Can you hear that noise? Where do you think it’s (it is) coming from?
It’s (it is) nearly the end of the month. It’s (it has) gone really quickly.

Its is a possessive determiner (like my, your, his) which we use when referring to things or animals:

Every house in the street has got its own garage.
[talking about a famous American journalist]
He joined the New York Tribune (1868), becoming its editor-in-chief and eventually its principal owner (1872–1905).

We don’t use its as a possessive pronoun.

Compare

A: Whose is this ball?B: Mine.	Possessive pronoun mine used alone.
A: Whose is this ball?B: The dog’s.Not: ~~Its.~~	Possessive determiner its is not used alone. We repeat the noun which is being referred to.