Was gonna add to that answer, but not sure there's anything to add really. But it was important to see my four thousand, three hundred and fifty first non-deleted post.
No! The broker will give you your $10,000 back plus profits when you close your position. The $10,000 is to ensure you don't run away when you start losing money.
Of course I only posted 723 times, so take my answer with a pinch of salt
Most brokers also have an intraday margin if you're thinking about daytrading. For instance the initial requirement might be $10k but the intraday margin might only be $2k. I've seen a lot with about a $2k initial and $500 intraday.