Once you know this easy and simple rule, you start seeing it wrong all over the place. It’s kind of amazing. And let’s not forget that English is a bit confusing and one of the more difficult languages to learn because of all the rules.
Just remember that “it’s” (with an apostrophe) always means “it is” and that’ll help you know when to use it.
Here’s an example:
Using “its” is possessive – meaning, it belongs to something.