"Its" is a possessive pronoun, meaning "belonging to it." It functions as an adjective and always goes before the noun it modifies.
* Example: The dog wagged its tail. ("Its" modifies "tail" and shows possession.)
"It's" is a contraction of "it is" or "it has." It functions as a pronoun and verb and cannot be used as an adjective. It always stands alone.
* Example: It's a beautiful day. ("It's" is a contraction of "it is" and acts as both the subject and verb.)
Here are some tips to help you remember:
* If you can substitute "it is" or "it has" for the word, use "it's."
* If you can't substitute "it is" or "it has," and the word is indicating possession, use "its."
Let me know if you'd like to see some more examples.