Other than deleting a specific column, if you want to delete entire columns from the report then click on “Remove All Columns” Option located above the report section.
After you click on “Remove All Columns” Option, an alert message comes to your screen that ask you “Do you want to remove all report columns?” If you really wish to delete the all fields then click on “OK” button, but if you do not want to delete then click on “Cancel” button.