You're talking about the kind of anxiety that only harms us, right? Since anxiety and fear are emotions that have a purpose-- to show us danger and modify our behavior to get away from danger.
If we grew up with a constant alarm that said: "Threat! Threat!" all the time, then our anxiety is probably ingrained(among other things like ADHD, depression, these are just strategies that get ingrained to try to survive).
It helps just to realize the way that works, even if you already had a bit of an intuition, just know that we're just expressing these emotions automatically and reactively, so the first part is having that knowledge. Emotions can connect to reality, but they can also horribly mislead, and cause us to suffer pointlessly(and cause people around us to suffer pointlessly too). Your suffering is always real, but the emotions aren't always right. But that doesn't solve it, right? That alone hasn't magically made it so you'll never suffer from anxiety again. What's the problem then, if it's not knowledge?. It's partly knowledge, but it has to be realized at the moment it's needed through awareness.
When we're having something like an anxiety attack, we're actually not aware or examining things. Isn't it that we're just totally lost in the emotion? It's holding us hostage from doing the thing we want in the way we'd want to. Compare the you right now, who isn't having an anxiety attack, who is more free to reflect calmly, to the you who is at peak anxiety. See how different that is? This may sound confusing but the main point is: the calm and reflective you right now, is accessible in the moment where you're lost in anxiety, through awareness.
It's being sensitive to that difference that can free you from any negative emotion. One of the simplest ways to start that is just to take a deep breath. Maybe it sounds unsatisfying because of how simple it is, but it really works. And you can condition yourself to do this the same way that your anxiety was conditioned, the more you repeat something, whether it's positive or negative, the more ignrained it gets. Close your eyes if you can, take some of the slowest, most careful breaths you can, see if you notice that this causes you to relax, and then from there just be curious and ask gently: "What is this anxiety? Where is it? What happens to it when it's observed? Does it stay? Does it change, or vanish?" You can even do this when you're not particularly anxious
