How can I review income for the year previous to last year on Quickbooks?

Let's run and customize the Profit and Loss report, shane22.

By doing so, we can pull up your monthly income for 2019 in QuickBooks Online. I'll show you how.

1. Go to Reports.
2. Locate and select the Profit and Loss report.
3. In the open Profit and Loss report, select Customize.
4. Enter the correct date in the Report period.
5. In the Customize report panel, select the Rows/Columns item to open the section.
6. From the Columns drop-down list, select Moths.
7. Filter the other details you'd like to add.
8. Once done, click on Run report.

For your visual reference, I've attached some screenshots below.

You can also run our Profit and Loss Comparison report in QuickBooks. This helps you compare your income and expenses for different time periods. 

Once you pull up the report, I'd suggest memorizing it in QuickBooks Online. This helps you save the current customized settings. This way, you can easily access it in the future.

I always here to show you what else you can do in your reports in QuickBooks Online. Please don't hesitate to get back on this thread. Keep safe.