Here you can set your Purchase Order Number Settings preferences as well as Purchase Tax settings. This setting does not apply to QuickBooks Purchase Orders.
If you choose to automatically generate your Purchase Order numbers you can choose a prefix as well as a starting point for your numbers. You can also choose to manually enter your Purchase Order numbers if you wish.
Here you can decide whether or not to include use tax on your Purchase Orders.
Purchase Orders can have two numbers associated with them. The SI Purchase Order Number (labeled "Number") and an Accounting Order Number (labeled "Accounting Number"):
The Accounting Number is automatically populated when the Purchase Order is sent to QuickBooks but you could also manually enter a value here if you are not using QuickBooks. There is an option to automatically replace the SI Purchase Order Number with the Accounting Purchase Order Number when the Purchase Order is saved.