How does Margin account work?

Share margin accounts are for you to borrow and invest with less starting capital. If you are new to investing, it is probably not a good idea because you would likely be over-investing.

I was new to investing during the 2007-2008 crisis and made this mistake of over-investing. Had to force-sell some shares to stay afloat which was a painful lesson.

You put a deposit.

They give you a margin multiplied by your deposit. Some margin accounts are low like 2 times, some can be insanely high 400x of your deposit capital.

With margin you can of course buy more than you can with just deposited capital. Every time you make use of the margin, you will be charged interest because you are technically borrowing money.