Hi, It can be used in similar ways, however, 'Here it is' directs attention to the object, whereas 'here you are' puts you as the subject and points towards the action. This is actually very difficult to distinguish in certain contexts... I hope this makes sense.

the pronouns ("it" and "you") are different so they imply different subjects. "Here it is" is referring to an object, while "Here you are" refers to a person (you). with a singular object, you use "is" and in the plural you use "are". for example: Where are my boots? --> Here they are. Where is my book? --> Here it is. With pronouns it goes like this: Where am I? --> Here I am. Where are you? --> Here you are. Where is she/he? --> Here he/she is. Where are they? --> Here they are. Where are we? --> Here we are. As you can see, "I" and "you" can be considered irregular as you don't use "is" for either of them and you use "are" for you even though it can be singular. I hope this makes sense!

The other answers are good, I just wanted to add that "here you are" is often used in the context of giving something: A: Can you pass me the salt? B: here you are!

I had the same question the other day, so, the only thing i'd like to add is that sometimes it's enough to say just "here" (e.g., when you're giving something to someone). And you wouldn't say "here it is" if the other person hasn't asked for the thing you're offering them but rather say "here (you are)").

Thank you all for helping me to understand.