Apple Inc.’s forthcoming foldable iPhone will include updates to the iOS operating system that enable iPad-like layouts and side-by-side apps for the first time, enhancing the device’s appeal for multitasking.

The product — Apple’s long-awaited entry into the category — will feature an interior foldable display roughly the size of an iPad mini, according to people with knowledge of the matter. There also will be an external screen that’s about the size of the display on a small iPhone.