Unable to customize my purchase order format

Thanks for joining the Community forum, @vkmdk.

As of now, customizing the Purchase Order(P.O) isn't available. We're unable to share the specific time frame to when it will be added as a feature. Although, I saw a few requests already and I understand how beneficial it is to your business. 

In the meantime, I encourage you to visit our blog site to keep up with any product updates or improvements in QuickBooks Online (QBO).

For more information about how P.O works in QBO, check out these references:

• Create purchase orders in QuickBooks Online
• Copy an estimate to a purchase order
• Bill created from purchase order has incorrect or higher amount

I'm looking forward to seeing any concerns with creating PO if there's any you can place them here. I'd be delighted to help. Have a prosperous day ahead!