Electricians

I find electricity intriguing, but can’t wrap my head around it. I have this vague idea that electrons move along a wire. I get stuck think that it has to be a complete circuit.

What does it really mean when I open an outlet and there are 3 wires?

I think you need hot for the incoming and negative for the outgoing to complete the circuit.

So what does the neutral do?

And then adding ground into the mix and daisy chain addition outlets. Throw in a switch and not you have a single wire? Doesn’t electrons have to flow in the signal wire? Why is that not a complete circuit?