Hi there, typicole.

Welcome to the Community. Let me share instructions to ensure you're able to view the item detail section on expense page in QuickBooks Online.

We need to enable the Show Items table on expense and purchase forms option in the Account and Settings in order for the Item details tab/line to appear on the Expense page. 

Here's how:

1. Log in to your QuickBooks Online account.
2. Go to the Gear icon at the upper right corner.
3. Click on Account and settings.
4. Select the Expenses tab.
5. Go to the Bills and expenses section. Then, turn on the Show Items table on expense and purchase forms.
6. Hit Save and Done.

Also, keep in mind that this is only available in the Plus plan. The Item details tab is not available in Essentials or Simple Start.

To view your vendor transactions in QuickBooks Online, you can check out this article for more information: View vendor transactions.

Let me know if you need further assistance about your vendor entries in QBO. I'm always here to help. Have a wonderful day!