To ensure you get the data that you need in QuickBooks Online (QBO), I suggest contacting the Storehub Support team. In this manner, you'll know what specific data Storehub can transmit when purchase order is raised in their system to QuickBooks when it synchronizes.
In addition, they know which settings to change in their application to integrate the data seamlessly in QBO accounting and recording system.
Furthermore, here are some references relevant to purchase orders: