If a woman is angry at something, or at you, what do you do to calm her down?

If she's violent, either with objects or towards you, leave, and don't come back until she's had plenty of time to calm down (minimum 20 mins, preferably the next day).

If she's just verbal, listen carefully and don't interrupt. See if you can memorise what she's saying, or write it down.
Later, when she's calm, have a talk about it.

People are always angry for a reason. Anger is a secondary emotion.
Underneath can be shame, fear, or pain.
The shame is usually toxic; the feeling of having done (or said) something wrong and having severe negative self-judgements about it; it's hard on the ego, hard to admit and it hurts unbearably, so the person lashes out, either consciously or unconsciously trying to make someone else responsible for their pain.
Fear happens when we perceive the potential for pain or loss, especially if it has happened before and is triggered by some similar situation or event. I can be fear of an emotional or physical attack, fear of loss of a person (they leave or love someone else), fear of loss of security (job, house, transport etc), or fear of danger such as an accident in a risky situation. The adrenaline pumps, and if the first response to the fear or anxiety does alleviate it, anger follows.
Pain can be physical or emotional. It can be at any level, such and being profoundly overwrought from grief or physical exhaustion, a head or back ache, too long tolerating hives, even being very hungry or thirsty. This can make a person less tolerant of minor irritations and more like to snap over something small.
All of these can be resolved by finding out what the person's need is, and then exploring how it can be met or fulfilled. When that happens, understanding, trust, and a better relationship is built.
There are specific ways to achieve this. Try listening to one of the YouTUbe clips of Marshall Rosenberg Discussing Compassionate or Non-Violent Communication.

There's also another thing to watch out for. Some people use anger and temper tantrums as means of trying to manipulate and control others. If that's the case, or you suspect it, then it's time to draw a boundary and say no. Let them have their rage; let it burn itself out. Let them learn that getting angry isn't going to solve anything. And if they refuse, consider leaving the relationship permanently, because such people are toxic and dangerous to be around.

One thing's sure, pinning a person down or forcibly trying to hug them when they're in a rage will never solve anything.
And it could get you arrested for assault.

My girlfriend will hold my hands in her hands and that always helps. She knows I can get really worked up but the simple touch let’s me know she’s with me... without invading my space.

Make me a sandwich, and shut the hell up as the football is on

Look at her with puppy eyes 🥺

Tell her to stop as she is acting like her mom again....I bet that works.

I tell her to calm down. Then prepare for the consequences.

Yes dear you are right

Buy her food.

What works with @HannibalAteMeOut is giving her human flesh to eat and a good wine to pair it with.

1. “Hey, let’s not fight when we’re actively pissed off”
2. Walk away for 20 minutes so she can collect her thoughts and put it all together
3. Listen

If she raises her voice at me I walk out the door and never come back

Calm the fuck down!!!!