The Apple 20W USB-C Power Adapter allows you to charge your devices quickly and efficiently at home, in the office, or on the move. 
While the power adapter works with any USB-C device, Apple advises using it with the 11-inch iPad Pro and 12.9-inch iPad Pro (3rd generation) for the best charging results. 
You may also use it to take advantage of the fast-charging feature if you have an iPhone 8 or later.