SAN FRANCISCO — Amazon.com Inc. is quietly inviting drivers for its new "on-demand" delivery service to handle its standard packages, as the online retailer known for low prices and razor-thin profit margins looks to speed up delivery times and tamp down its growing multibillion-dollar logistics bill.

Amazon.com Inc.'s China arm has registered as an ocean freight forwarder, according to the U.S. Federal Maritime Commission, a move that will give it more control over shipping products from Chinese factories to U.S. shoppers.