You can connect your MacBook (Retina, 12-inch, Early 2015) and later or your late-2016 MacBook Pro to Ethernet in two ways.
Use a USB-C to Ethernet adapter
Connect a USB-C to Ethernet adapter to the USB-C port on your MacBook or one of the Thunderbolt 3 (USB-C) ports on your MacBook Pro. Then plug the Ethernet cable into the adapter.
When you use a USB-C to Ethernet adapter, you can't charge your MacBook at the same time.
Use USB-C to USB, Digital AV Multiport, or VGA Multiport adapter along with an Apple USB Ethernet Adapter
Connect the Ethernet cable to an Apple USB Ethernet Adapter or a third-party adapter. Then, connect the adapter to the USB port on any of the following USB-C adapters:
Connect this assembly to the USB-C port on your MacBook or one of the Thunderbolt 3 (USB-C) ports on your MacBook Pro to access Ethernet.
*The USB-C Digital AV Multiport Adapter and USB-C VGA Multiport Adapter are powered, so they can charge your computer while also connecting to Ethernet or other devices.