I appreciate you following the steps provided by my colleagues above to show the SKU column on a purchase order, @daniel67. 

I've got other steps for you to show the SKU column on a purchase order. And the steps are quick and easy. Here's how:

1. Click the Gear icon, then select Account and Settings.
2. Select the Sales tab and go to the Products and Services section.
3. Mark the Show SKU column box.
4. Click Save and hit Done.

After turning on the feature, the SKU column will be visible to your purchase order form.

On the other hand, the description of the product and services will show depending on the transaction. Based on your example, the description for sales information (A) will show on sales transactions, like invoices, sales receipts, or estimates. While the description for purchasing information (B) is for purchasing transactions, like PO.

I'm adding these articles for more guidance:

• Customize your invoices, estimates, and sales receipts in QuickBooks Online.
• Add your product’s name, SKU, and category.

Please get back to me if you have further questions. I'll be more than glad to share additional insights and assistance whenever you need it. Have a wonderful rest of the day!