How can I view all expenses in a particular category?

It's nice to see you here in the Community forum, @don50.

We can pull up the Profit and Loss report. It will show a summary of your expenses in a particular category. I'll guide you how:

1. In QBSE, go to the Reports menu at the left pane to get to the Reports page.
2. Click View in the Profit and loss.
3. Click the drop-down at the top right, then customize the Date range.

To know more about expense categories and how they are shown on Schedule C report, please click this article: QuickBooks Self-Employed Schedule C Categories breakdown.

Just in case, I'll add this article: Taxes And Forms Overview In QBSE. It provides you more details about managing your taxes and forms, such as running any financial reports.

If there's anything else I can help you managing your QuickBooks account, please let me know by commenting below. I'm more than happy to further assist you.