Great question! 

You'll need to create a custom report in your Square Dashboard to view this specific information. 

In your Square Dashboard, click on the "Sales" tab and select "Category Sales."

In the bottom left corner of the screen, under "Custom Reports" you can click "Create New Report."

Hovering your cursor over the Category Sales section will allow you to click on the "Filter By" dropdown. This will allow you to list all of the sales by category, and also pick and choose which categories appear in this report. 

In order to have taxes appear, you'll want to click on the "Edit Columns" drop down and make sure the taxes box is checked. 

Click "Save Report" in the top right corner and this report will be available to you going forward.