its is the possessive form of the pronoun "it", used to indicate that something belongs to or is associated with a thing previously mentioned or easily identified.
Common usages of its:
1. The dog wagged its tail.
2. The company is known for its innovative products.
3. The tree has lost all of its leaves.
Note: Don't confuse its with "it's" (contraction of "it is" or "it has").