You can run the Transaction Detail by Account or Custom Summary report if you needed to show different expense category. Here's how:
Click on the Reports tab.
On the search box type, Transaction Detail by Account or Custom Summary report.
Click on Customise button.
Select a Report period.
Click on Filter, and under Distribution account select All Expenses Accounts.
Click on Run report.
The report should show all transactions and expense account used in QuickBooks Online. Repeat the same process in customising the Customer Summary Report.