We can either use Check or Expense transaction, jb1203.

In QuickBooks, the Purchase Order (PO) is a non-posting transaction. That being said, it will not reflect on your Profit and Loss and any product quantity reports.

We'll have to manually use either Check or Expense to bring in and track the items you've received from your vendor. 

You can do that by clicking the + New button and then select either Check or Expense. Then, select the items under the Item details field.

Feel free to browse this article if you want to adjust the item's quantity on hand: Adjust inventory quantity on hand in QuickBooks Online.

Let me know if you still need help. Stay safe!