• its
'Its' is a possessive pronoun. It means that it shows the ownership of something. Unlike 'his' or 'hers', it is not gendered therefore it can refer to a non-human or non-gendered human's possession.
- The dog loves its new toy.
• it's
The word 'it's' is the contraction of two words, 'it' and 'is' or 'has'. Whenever someone wants to say 'it is' or 'it has', 'it's can be used.
- I love pizza. It's very tasty. (It is very tasty.)
- It's got to be a joke. (It has got to be a joke.)
• Confusion
There is a confusion because apostrophes are used to show possession.
- The cat's paw.
But it does not mean that the possession of 'it' is 'it's'.