CloudSupply is a barcode inventory tracking software and it was built around the idea that barcode scanners would be used to remove stock. A barcode scanner is just a keyboard, as far as a computer is concerned. To add barcode scanning to your computer, all you have to do is buy a usb barcode scanner.
The one that I use and recommend is below:
I tried this device on my MAC, Rasbperry Pi, and Windows machine and it worked just fine.