Let's make sure that we'll be able to pass the Purchase Order (PO) concern to our developers, RoscoPC.

I know how this will greatly benefit your business. You can use this link: http://feedback.qbo.intuit.com/ to submit feedback to our developers by clicking the Give feedback link. I've added this screenshot for your guide:


You may also want to check out other feedbacks being submitted and vote for them for more chances of implementing it. 

For your reference, you can also record expenses by entering them as bills. Go through this article for more information: Enter Bills And Record Bill Payments in QuickBooks Online.

Let us know if you have any questions about PO. As always, we're here to make sure you get the help you need.