Dear JKS,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
Per the description shared, I would like to summarize your concern i.e., you have inserted the PivotTable in the Excel workbook but you can't see the PivotTable Field List.
If my understanding is correct, first, I would like to convey to hide the PivotTable Field list completely, we either need to click on the Hide Field List (by right-click on the PivotTable and clicking on Hide Field List) or Click on the Field List in the PivotTable Analyze tab.
If you can see the Field List button is enabled in the PivotTable Analyze tab, like the below screenshot, it means the Field List should be visible:
If the button is enabled and you can't see the PivotTable Field, can I know whether you are using the extended monitor? If yes, please check whether the PivotTable Field is moved to the different monitor.
If not and still it's not displaying, turn off and turn on the Field List button in the PivotTable Analyze tab. If turning off and turning on doesn't display the Field List, I would like you to perform Online Repair to the Office apps and check the outcome. Reference: Repair an Office application (microsoft.com)
If still not, we would like you to share the screenshot of the Excel app Account page. Open the Excel app> Account> Take a screenshot and share it with us.
We look forward to your response. Thanks for your cooperation.
Sincerely,
Mia | Microsoft Community Moderator