LAGUNA BEACH, Calif.—International Business Machines Corp.’s Watson artificial-intelligence technology is on track to be used in some form by a billion people by the end of next year, Chief Executive Virginia Rometty said Wednesday.

Ms. Rometty, speaking at The Wall Street Journal’s WSJDLive 2016 technology conference, pointed to the company’s new deal with General Motors Co. to pair Watson with GM’s OnStar system in cars as an example of how IBM is extending Watson’s reach. She said such partnerships will have put Watson...