Hi @Anonymous
We can update Sharepoint with the Barcode number. Ideally, Sharepoint should have a few columns
Employee-Person Field
Serial Number - Number or Text

Using PowerApps, You will be having a form to create or edit an existing item. The form should have Employee as Combo box and Text box for the Scanned Value

Set the Items property of person combo box to
Choices([@'Device Inventory'].Employee)
Set OnScan property of Barcode Scanner to
Set(DeviceSerialNumber, BarcodeScanner1.Value)
Set the Default property of Serial number text control to
If(IsBlank(Parent.Default), DeviceSerialNumber, Parent.Default)
And submit the form
SubmitForm(EditForm1)
Let me know I can help with more details
Thanks,
Stalin - Learn To Illuminate