Answer:
You're in luck because surprisingly I know a thing or two about it.
So, basically buying a stock on margin means to borrow money from a broker to purchase stock. Think of it as a loan from your brokerage. Margin trading actually allows you to buy more stock than you normally would be able to. To trade on margin, though, you need a margin account, and a minimum of at least $2,000 is required to open one.
Hope I helped :)