Good morning, @Brita2.

Thanks for reaching out to the QuickBooks Community. I hope you're having a wonderful day so far. 

At this time, QuickBooks Desktop doesn't have the option to create a new barcode from the purchase order and item receipt screens. However, you can set up your barcode and scan it to fill out a purchase order and item receipt. 

I'm including some steps below that cover how to set up a barcode scanner and how to generate barcodes. 

1. In QuickBooks Desktop, go to the Edit menu and choose Preferences.
2. Select Items and Inventory, then select the Company Preferences tab.
3. Click on Advanced Inventory Settings, then tap the Barcodes tab.
4. Hit Enable Barcode, then select Open Barcode Wizard.
5. In the Barcode Scanning Setup wizard, click which item field you want to use for barcode tracking. If you’re not sure what to use, choose a field that will be unique for each item, such as the Item Name or Part Number. Then tap Next.
6. Select the types of items you want to generate barcodes for. Click Next, then Finish.

Once your scanner has been connected and the barcodes have been generated, you can scan them to add them to your transactions. Here's how: 

1. Open a transaction in QuickBooks Desktop.
2. Scan an item with your barcode scanner connected to your computer. The item will appear on the transaction as a new line item.

You can scan barcodes to fill out any of these transactions:

• Estimates
• Sales Orders
• Invoices
• Sales Receipts
• Refunds & Credits
• Purchase Orders
• Item Receipts
• Bills
• Write Checks
• Inventory transfers

For more detailed information about this process, check out Set up and use barcode scanning in QuickBooks Desktop. 

Please don't hesitate to let me know if you have any additional questions or concerns. Take care!