Hi there, rkoorapati.

I understand the importance of customizing the purchase order form. However, you can only customize transaction forms such as invoices, sales receipts, and estimates on the online version of QuickBooks.

As a workaround, you can create custom fields for the additional information to be captured for the purchase order items. Here's how:
 

1. Go to Settings ⚙. then select Custom fields.
2. Click Add custom field. If you’ve already created a field, you’ll see Add field instead.
3. Enter the name of the custom field.
4. Select the type of data that will go in your custom field: Text and number, Number only, Date, or Dropdown list.
5. Choose the category the custom field belongs to: Customer, Transaction, or Vendor. 
   
6. Mark the forms where you want the custom field to appear. 
7. If you want customers or vendors to see the field on a form (such as invoices, estimates, or purchase orders), toggle the Print on form. 
8. When you’re finished, hit Save.
9. Once done, you can create the purchase order.

You can find more details about the steps above through this article: Create and edit custom fields in QuickBooks Online Advanced.

In the meantime, you can check out our blog for the latest happenings, feature developments, and product updates: The QuickBooks Blog. It also includes the link to our resource center where you can find tips on how to effectively manage your business.

I hope this gives you peace of mind. Please let me know if you have other concerns. I'm just around to help. Take care always.