Welcome to the thread, Noem101.

In QuickBooks Online, you can enter more than one item on the Purchase order with their SKU number on each row. You'll just have to make sure that you're able to add SKU to a product or service items.

Once your supplier accepts the purchase order, you can add it to an expense or bill to make the transaction official. 

Here's how:

1. In the left menu, click the + New button.
2. Choose Expense, Cheque, or Bill. 
3. From the Payee ▼ dropdown, select the supplier. This opens a window with their open purchase orders.
4. Select Add for the correct purchase order. This adds the items from the purchase order. They appear in the Item details section.
5. If you plan to bill a customer for a specific item, select the Billable checkbox. Then add the customer you plan to bill in the Customer column.
6. Select Save and close.

For more details in handling purchase order, see this article: Add purchase orders to expenses, bills, or cheques in QuickBooks Online.

Alternatively, if you wish to have the SKU displayed on a purchase order, you can input it manually into the Description field. As a result, the SKU will be visible in the Activity or Description column when the transaction is printed.

Let us know if you have any other concerns, Noem101. We're here to help.