How do i upgrade my system and add in purchase orders

Welcome and thanks for visiting the Community, @info-securedlivi.

The Purchase Order (PO) option is only available in both QuickBooks Online (QBO) Plus and Advanced versions. If you're using Simple Start, here's how to upgrade your account:

1. In QBO, go to the Gear icon at the top right to get to the Account and Settings. 
2. Select the Billing & Subscription menu at the left pane.
3. In the QuickBooks Online section, tick Upgrade.
4. Pick the plan you want, and click Upgrade.
5. Confirm your payment information, then hit Save.

After that, you need to turn on the PO feature in your new account. Here's how:

1. Go back to the Accounts and Settings.
2. Select the Expenses menu at the left pane.
3. Click the Edit (pencil) icon in the Purchase orders section. 
4. Place a checkmark on the Use purchase orders box. 
5. Hit Save and Done.

If you want to more about using PO in QBO, I highly suggest checking out this article: Create purchase orders. It also includes the types of reports that you can pull up.

You also have the option to add PO to cheques or Bills. Refer to this article for further guidance: Apply a purchase order to a supplier transaction.

Please let me know if you have any other questions or concerns. I'll be more than happy to help. Have a great day!