We're unable to customize the form and take out the product/service column, MC2458.
Customizing a purchase order can be a good idea, though. I'll take note of your concern and submit this to our management team. All your ideas and suggestions are forwarded to our software engineers. This feature may be added in future updates.
I'll also add the reference on how to create purchase orders in QuickBooks Online. This helps you find out how this transaction works for your business.
If you have additional questions, I'm just around. You can tap me, and I'll get back to you as soon as I can.