Yes. This is possible. In terms of scanning a barcode, there are a number of ways of doing it with perhaps the first option being to take a look at this document which talks about using the built-in UWP BarcodeScanner class with image frames from the HoloLens web camera in order to scan barcodes.
This works on HoloLens. One challenge though (if I remember correctly) is that this document assumes you want a 2D UI using the system's preview capability. On HoloLens, you are perhaps working in a 3D/Unity environment and you probably don't need to preview what's coming from the camera because you can already see it! I wrote some code around that idea here although it could now be a little out of date but might give you some pointers.
If you now have a barcode, how to get it to your PC? There are lots of ways that you could do this. You could use traditional networking techniques like having a datagram/stream socket between the two devices. You could use something like Bluetooth to advertise the data & pick it up. You could combine the two techniques and I have some old code here which you might repurpose to do just that.
You could use a cloud mechanism like an Azure queue. You could have both devices connect to a cloud service (like a SignalR implementation) and pass the information that way. You could use something like "Project Rome" to invoke a remote 'app service' on another device.
I hope that helps a little - the main thing is that this is definitely achievable, you just need to pick the way that's best for your scenario.