That’s why a network connection for the printer is preferable. If the printer is connected to your computer instead of the network, then your computer can share the printer so other computers can use the printer, but your computer needs to be on to do that. This way, all the devices can use the printer. Otherwise, you can buy a router which connects to your internet device on the WAN side, then all your computers, tablets, printers, etc connect to the router on the LAN side. Your cable modem or whatever device you use to connect to the internet (WAN or wide area network) might have a built in router or maybe built in wifi router. Your computer will be able to find the printer on your local area network (LAN).
If your printer has an ethernet or wifi connection ability (to allow connecting it to a network), then you should use that instead, so that you don’t need to connect it directly to your computer. I believe a USB 2.0 Type-B plug will connect to a USB 3.0 Type-B plug, but it will not support USB 3.0 speeds. That will determine which kind of USB-B male connector you should get. Check the printer’s end of the cable to see if it is USB 3.0 or USB 2.0. Or you can replace the printer’s existing USB cable with a USB-B male to USB-C male cable. Make it easier for other people to find solutions by marking a Reply Accept as Solution if it solves your problem. Click the KUDOS thumb up on the left to say Thanks. The adapter should support USB 3.1 so it can be used with all USB devices, not just USB 2.0. Please use the following USB cable (A to B, male connectors): You can try USB 3.0 port but may not work. You need a USB-A female (receptacle) to USB-C male (plug) adapter, which can connect your printer’s existing USB cable to your computer.
The Thunderbolt 3 port is also a USB 3.1 gen 2 USB Type-C port (well, it is a USB Type-C port supporting USB 3.1 gen 2, and has Thunderbolt 3 as one of the supported USB-C alternate modes). Printer Cable, Deegotech 6.6ft USB C Printer Cable for MacBook Pro, USB B to USB C 2.0 Cable, Nylon Braided Printer Cord Compatible with MacBook Pro Air.