Apple’s upcoming 2019 iPhone models will “likely” include a faster 18W USB-C power adapter and a Lightning to USB-C cable in the box, according to Japanese blog Mac Otakara (as noted by MacRumors).

This sort of fast charging functionality is available for the iPhone 8, iPhone 8 Plus, iPhone X, iPhone XR, iPhone XS, iPhone XS Max, and iPad Pro users, but requires customers to use a $49 USB-C MacBook power adapter (pictured) or a third-party USB-C power adapter (about 15 bucks) paired with a Lightning to USB-C cable. The latter costs $25 and is only available as a standalone accessory.
Chances this rumor is true, according to the Sellers Research Group (that’s me): 90%. It makes sense. USB-C fast charging would allow an iPhone to charge from 0-50% in roughly 30 minutes.