SEOUL— Samsung Electronics Co. is planning to roll out new voice-assistant features to challenge its U.S. rivals’ dominance in artificial intelligence, following stumbles as it wooed app developers.

At an event in San Francisco next week, Samsung will fully open its virtual assistant, called Bixby, to third-party developers for the first time. It is looking for help in bolstering its challenge to the industry’s big three players: Amazon.com Inc.’s Alexa, Apple Inc.’s Siri and Alphabet Inc.’s Google Assistant.

Samsung will outline how developers can create functions, which it calls “capsules,” that are akin to the “skills” that Amazon’s Alexa assistant has, such as ordering pizza or hailing taxis with a voice command, according to people familiar with the matter.

Samsung will also share more details about a foldable-screen smartphone it is developing, showcasing features of the tablet-sized handset, such as the simultaneous use of three apps, according to the people, though those plans haven’t been finalized.

The Suwon, South Korea-based company has held discussions with YouTube, a unit of Google parent Alphabet, and Netflix Inc. on how to optimize content for the foldable-screen device, the people said. Google and Netflix declined to comment.