Investing on margin allows you to increase your buying power (and therefore, leverage) by borrowing money from your broker (SoFi). The securities that are purchased serve as collateral for the loan, and interest is assessed on the outstanding loan balance.
Using leverage through margin investing will increase the magnitude of both gains and losses on your investments. And if the value of your securities decreases, you may be required to add funds or liquidate a portion of your portfolio to pay back the loan. (This is known as a margin call.)