In the Products List of a Purchase Order, the Multi-Inventory products will be marked with the Multi-Inventory green icon. Also, you will see the list of the product's inventories used in the Purchase Order.
In each inventory row, you will see the Cost, Quantity, and Total Amount for this inventory.
You can hide the list of the product's inventories by clicking on the Multi-Inventory Green Icon.
To view the inventories' details, click on the expand icon located at the right of the Inventory row.