Wifi
Wifi is special type of wireless technology for local area networking of devices based on the IEEE 802.11 standards. Wi‑Fi is a trademark of the Wi-Fi Alliance. This technology can be used for very rapid transfer of data in the form of images, videos, contact etc.
USB
Universal Serial Bus or USB is a connection standard to connect peripherals like digital cameras, keyboard, printers, etc. USB can be act as a power supply and for charging of mobile devices.
There are three generations of USB specifications:
USB 1.x,
USB 2.0,
USB 3.x.