How do I add/remove totals from a pivot table?

Here’s another FAQ we get:
How do I remove the “Totals” section of the Pivot table?
and the converse:
How do I add a “Totals” section to my Pivot Table?

You can turn on and off the “Show totals” of a pivot table by using the dropdown menu on the column in question in the left hand side configuration panel:

Added Pivot, Table