"Its," with no apostrophe, is a possessive pronoun. It is the neuter equivalent to "his" and "hers." I am Dan. My hair is grey. (My hair belongs to me. I "possess" my hair; hence "my" is a "possessive pronoun.") You are Camillo. Your hair is black. This is Sam Brill. His hair is brown. This is Rosa Brill. Her hair is blonde. They live in this house. Its roof is green. (This is the "third person singular," and it is the only place where there are different pronouns for the masculine, feminine, and neuter gender). We are the Smiths. Our house has a grey roof. They are the Brills. Their house has a green roof. There is a completely different word, "it's," which is pronounced exactly the same way as "its." "It's" is a contraction of "it is," and means the same thing as "it is." What's that sound? It's the sound of the wind blowing through the trees. Where is the Statue of Liberty? It's in New York Harbor.

Even native English speakers spell this incorrectly very often! So you may see it written incorrectly as much as you see it done the correct way. That will be confusing. The above answer from Dan Smith is a very good one. :) When we want to say, "It is." We can choose to squish it into a shorter word - combining both together, but replacing the second 'i' with an apostrophy - "It's". But you are asking about "its". With no apostrophe, it means ownership. This is a break from the usual possessive rule (show possessiveness with an apostrophe and an S) in the English language. One of those things you just have to remember. Take heart that many native speakers don't get it correct. ;) The table has its centerpiece. The dog has on its collar. The lamp is missing its bulb. The glass is in its cupboard. The canary is in its cage.