How do I delete a line from Item details in purchase orders?

Let's clear out some line items in your transactions, tom-kentmold-com.
 

The Auto-recall feature might have been activated in your account. This is why the program automatically filled the purchase order with the details from your previous entry. This feature basically uses the information from the last saved transaction type for that specific customer, vendor, or employee.

You can turn it off or on by following these steps: 

1. Go to Settings ⚙, then select Account and Settings.
2. Proceed to the Advanced tab.
3. In the Automation section, select the pencil icon.
4. Look for Pre-fill forms with previously entered content to enable auto-recall. Uncheck the box to disable the auto-recall feature.
5. Select Save at the bottom of the Automation box, then Done to record your changes.

You can read more details about this feature here: How To Use Auto-recall To Pre-fill transactions.

I will also guide you on the process of removing lines from purchase orders and other transactions in QBO. 

Just navigate to the specific line item you wish to remove, and then select the Delete icon located on the far right of that item.

Should you need further materials regarding the process of recording POs in QuickBooks Online, the following articles and resources can be quite beneficial:

• Bill Created from Purchase Order has Incorrect or Higher Amount
• How to Run Purchase Order Reports

I'll be keeping an eye out for any additional questions you might have while recording transactions in QBO. Feel free to return to the Community if you need anything else from us.