Apple recently released a 35W Dual USB-C Power Adapter. Now the company has published a manual for it. Discuss
Apple said that to charge onedevice, you need to connect it to any USB-C port. To charge two devices, you also need to connect them to any of the ports: the power is automatically distributed between them depending on the requirements. For example, if you connect a MacBook and an iPhone or iPad, each device will receive up to 17.5 watts. But in the case of a Mac or iPhone and Apple Watch or AirPods, a laptop or smartphone will receive up to 27.5 watts, and a watch or headphones up to 7.5 watts.
If any device requires more power, you need to disconnect the second device and its charging cable from the power adapter.