The USB-C to USB Adapter connects a Mac that has a Thunderbolt 3 (USB-C) or USB-C port to a device that uses a USB-A cable.
To connect an iPad Pro or iPad Air with USB-C to the USB-A port on a Mac, use a third-party cable, such as the mophie USB-A Cable with USB-C Connector.
Data transfer and charging other devices
Use the USB-A port of this adapter with flash drives, cameras, USB hubs and other devices that connect to USB-A for transferring data or charging. It supports data transfer speeds up to 5 Gbps (USB 3.1 Gen 1).
For example, you can connect the Apple Lightning to USB Cable to this port to sync and charge your iPhone, iPad or iPod. Or use the Apple USB-C to Lightning cable to connect your iOS device without an adapter.
This adapter doesn't require any power to operate, but devices that you plug into it may draw power from your Mac. To connect to USB-A devices and charge your MacBook at the same time, you can use the Apple USB-C Digital AV Multiport Adapter or Apple USB-C VGA Multiport Adapter, which also provides a USB-C port for charging.