Anything is a word that appears commonly throughout everything. I personally favor the word anything. It tops everything else that means anything. Anything means to refer to a thing, no matter what. That could really mean anything if you think about it. It could mean this, that, or everything, it really isn’t specific but I feel that it still gets the job done, anything could even be a hyperbole. “She hasn’t said anything!” even if she said a few words. That literally makes no sense, I know, but don’t worry it doesn’t mean anything.
Everything means everything, but not everything in the world. Like everything in a specific area. It can even be metaphorical, like for example, “Everything is going horribly wrong!” Now it isn’t in a literal sense, It’s actually saying that just the one thing that they are trying to do is going wrong. If you take the word “wrong” out of that they could be talking about their life but it’s also a hyperbole. Now after looking at everything, anything and everything are similar but still extremely different and are both suitable for their respective situations. Make sure not to leave one out, I do not recommend using only one. Use both anything and everything, because they’re both unique and interesting words.