Wireless keyboards, trackpads, and printers do not need to use a USB port—these use wireless Bluetooth or Wi-Fi technology. Learn more about using USB devices with Mac computers here. Thunderbolt: Connect a Thunderbolt display, or connect a Mini DisplayPort to DVI, VGA, HDMI, or DisplayPort adapter. read more
If you have a device that doesn't connect to this port, you might be able to use an adapter to connect it. USB-C has the same shape as Thunderbolt 3 (USB-C), but doesn't support Thunderbolt devices. If your Mac has only one port like this, it's a MacBook with USB-C. read more
USB is an industry standard for connecting computers and other devices. Many Mac computers have USB-A ports (sometimes referred to as USB 3 ports), which look like this: USB 3.0 and USB 3.1 Gen 1 can transfer data up to 5 Gbps, and USB 3.1 Gen 2 can transfer data up to 10 Gbps. read more