After making a Pivot Table, you can add calculated items. Please see steps below:
Step 1: Click any cell in the item column which you want to add, e.g., "Region";
Step 2: Click the "Analyze" Tab from the Ribbon (or the PivotTable Analyze Tab in Excel 365);
Step 3: Click "Fields, Items, & Sets" in the "Calculations" section;
Step 4: Select "Calculated Item" from the drop-down list;
Step 5: In the new window, type the name of the calculated item, and click "Add";
Step 6: Click "OK" at the bottom. The new calculated item will show in the list.