Adafruit Feather HUZZAH ESP8266 Manual page 33

In order to upload code to the ESP8266 and use the serial console, connect any data-
capable micro USB cable to the Feather HUZZAH and the other side to your
computer's USB port.
Don't forget you will also need to install the SiLabs CP2104 Driver:
On Mac OS 10.13 and higher, in addition to installing, you will have to give the CP2104
kernel driver permission to load. You can find out if you need to give additional
permission by visiting your Security & Privacy settings system preferences screen
after installing and looking for the message that says, 'System software from
developer "SiLabs" was blocked from loading', like in the picture below.
To allow the driver to load, click the lock icon, enter your password, and click "Allow"
next to the warning message. After that, you may have to restart your computer
before following the steps below and connecting to your Huzzah in the Arduino app.
If you are using Mac OS 10.12.6 (Sierra) and you cannot upload with the latest
Mac OS VCP driver, please try the legacy v4 driver below. Note you will need to
uninstall the v5 driver using uninstall.sh (in the driver package)
©Adafruit Industries
Click here to download the CP2104
USB Driver
https://adafru.it/vrf
Page 33 of 53