Let me share an alternate solution on how to add the purchase order number field to your sales forms, userlindsay1.

As my colleague previously stated (DebSheenD), a purchase order is a vendor transaction. While invoices and packing slips are customer transactions. Thus, the purchase number information will not show on the sales forms. 

As a workaround, you can add a custom field to show the information mentioned above on your sales forms. Let me help and show you the steps.

Here's how:

1. In your company, head to the Gear icon in the upper right and choose Custom fields under Lists. 
2. Click the Add field to open the Add custom field screen.
3. From there, enter the name you wish to show on the invoice. For example, purchase order number.
4. Mark the All Sales forms or Purchase Order box, or mark both options.
5. Turn on Print on form feature to show the custom field on printed and delivered forms. Otherwise, it’ll only appear in QuickBooks Online.
6. Click Save to keep the changes. 

This reference covers all the details on how to create custom fields for your invoices, sales receipts, refund receipts, quotes, adjustment notes, and purchase orders: Add custom fields.

I can see how beneficial to a lot of users to have a built-in field for the purchase order number on sales forms. Incorporating this feature will surely improve your overall working experience. We can forward this product suggestion to our engineers and may add it in future updates.

Here's how:

1. In your company, tap the Gear icon in the upper right and choose Feedback under Profile.
2. Enter a brief description of your concern. 
3. Press the Next button to submit.
   

You can visit the New Features For QuickBooks page to learn more about the latest innovations and product updates. Also, the Sales and customers link contains a list of topics that will help you manage your payments, customize your sales forms, and process refunds or credits to name a few. 

If you have any clarifications or questions about purchase orders and invoices, drop a comment below and tag my name. I'll jump right back in to assist you further. Have a great weekend.