Final answer:
The PivotTable Field List task pane contains the fields available from the selected data source to be used in the PivotTable report, allowing users to customize their data layout.
Step-by-step explanation:
The PivotTable Field List task pane contains a list of fields in the data source you selected for the PivotTable report. When you create or modify a PivotTable, the Field List task pane appears automatically, showing available fields from your data set that can be used for organizing and summarizing your data in different ways within the report. You can drag fields to different sections in the PivotTable to adjust the layout of your summary - for example, set certain fields as filters, columns, rows, or values.