Let's consider a use case: showing all won opportunities and cases related to the accounts in one report for the last year. Remember that, as of the Summer '17 release, the Joined report is available only in Classic, so you need to do the following in the Classic user interface only:
- Navigate to the Reports tab and click on the New Report... button.
- Select the Opportunities report type; it is under the Opportunities category.
- Click on the Create button to continue.
- Change the Show field to All opportunities.
- Change Date Field to Close Date and Range to Previous CY.
- Click on the Remove All Columns link, click on OK to confirm, and then add these fields to the report: Opportunity Name, Account ...