Ladies of U.S.A insurance! !?!?!?!?

summer. • Trying for a 3rd baby
Im from the uk and as you know we have the NHS me and my parter was having a discussion on how your health insurance works and we sort of understand but can you explain to me in more depth like cost? What if you dont have insurance and does your work pay? And to be covered buy everything is that really expensive or is it just the rich that get that????