The Table Tools aren’t available on the ribbon in Excel Online, so you won’t be able to use them to make design changes to your table.
Though Excel Online doesn’t have Table Tools, some of the options are available. Here’s where you can find them:
Refresh data connections: Click any cell in the table > Data and pick either Refresh Selected Connection or Refresh All Connections.
Toggle total and header rows: Click any cell in the table > Format as table and choose one of the toggle options.
If you have the Excel desktop application, you can open your worksheet there and use the Table Tools to make design changes. Here’s how:
Click Open in Excel.
Click any cell in the table and Table Tools becomes available. You can use the Design options to make changes to the table.
When you save the workbook and reopen it in Excel Online, you'll see the design changes you made.
For news about the latest Excel Online updates, visit the Microsoft Excel blog.