It would be great if PivotTable is also included online especially if you have things to modify in the table.
Inserting new Pivot Tables in Excel Online is now possible. It is also possible to edit existing Pivot Tables in Excel Online workbooks.
Gregory Appel commented
For more info on the feature please visit this Microsoft blog post: https://techcommunity.microsoft.com/t5/Excel-Blog/Insert-new-Pivot-Tables-in-Excel-Online/ba-p/167548