OTG is an adapter connection that allows some devices' USB connections to work as hosts. On the Raspberry Pi Zero, we can use a USB OTG adapter to connect any USB device, whether it's a webcam, keyboard, or printer.
You will need a micro-USB OTG adapter. One end is the male micro-USB to connect to the Raspberry Pi Zero, and the other end is the female standard USB to connect devices (such as mice or keyboards). You'll also want a powered USB hub.
A typical USB OTG adapter will look like this:
Micro-USB OTG adapter
A USB OTG cable is really a must-have when starting out with the RPZ. It converts the micro-USB male connections to a standard USB female connection. With that and a powered USB hub, you will have no problem connecting a keyboard, mouse, USB storage, or devices such as Wi-Fi or Bluetooth. We will look at different ways of implementing more low-profile things such as Wi-Fi later, but a hub is the easiest way to get started.
All you need to do here is connect your OTG adapter to your Raspberry Pi Zero, and then, your powered USB hub to the other end of the OTG adapter. On your hub, connect your keyboard and mouse. Before too long, we will have the hub filled with peripherals, and then we will look at better ways to access (and accessorize!) the Raspberry Pi Zero.