When someone has "executive presence" we feel it. They are relaxed in a room of strangers. They take the microphone and immediately have something to say. Their energy fills the room. They don't have be loud or even energetic. But you know it when you feel it.
Executive presence is a skill. Some come by it naturally, but everyone can be taught. And I'll give you the punchline right now:
It's about teaching yourself to relax in situations where your body wants to do anything but relax.
I can show you how to do this. Some of it is technique. Some of it is neurophysiology. Some of it is practice. But everyone who learns this feels this difference.