The battered white van came to a stop outside Knickerbocker Village, a middle-income housing complex on the Lower East Side, carrying five workers who sat knee-deep in the printed advertising circulars known as mailers. On the ride from a warehouse in East New York, Brooklyn, they had folded hundreds of mailers and stuffed them into individual plastic delivery bags.

Now the workers — Haitian immigrants who mostly don’t speak English — dumped the mailers into large trash bags, which they loaded into repurposed baby carriages and wheeled toward the buildings like nannies.

The crew is part of an all-but-invisible army of workers who blanket the city each week with offers for things like Hot Pockets, yogurt, laundry detergent and even pumpkins. Retail stores — including national chains like Rite Aid and Best Buy and local supermarkets like Key Food and C-Town — hire a New Jersey marketing company called CBA Insert Distribution Network, which dominates the city’s five boroughs, to distribute weekly coupons and offers straight to consumers’ homes. CBA, in turn, hires about 200 independent contractors to drop the advertisements on brownstone stoops or hang them on door handles in large apartment complexes like Knickerbocker Village.

“I’m like the ghost of the coupon man,” Ricard Cardichon, 26, the van’s driver and the boss of the group, said on a recent Wednesday. “Sometimes I tell people, you know the coupons you see in the little papers, in the bags? Well, I’m the guy who’s responsible for it. And they’re like, O.K., sure, yeah.”