A direct funder underwrites your file, decides whether to approve it, sets the price and wires the money. Some take applications straight from business owners, and many also accept files from brokers.
The label is used loosely. Some companies that market themselves as direct funders also broker deals to other funders, and some bring in outside investors through syndication. Ask who will sign the contract, whose money you receive and who will collect the payments.
Going direct does not guarantee a lower price, and a broker does not automatically add cost. Compare offers on the total payback, the dollar cost, the payment schedule and the estimated APR, whoever presents them.